1. I'm being asked to find the arc length of y = sin(x) y = sin ( x) for [0, π 2] [ 0, π 2] using M8 M 8. I've determined that y′2 =cos2 x y ′ 2 = cos 2 x. So, using the formula for arc length, I get 1 +cos2 x− −−−−−−−√ 1 + cos 2 x as my function. Now, they want me to evaluate this using M8 M 8, so I end up with 8 8 ...Q. Integrate w.r.to x. tan−1( √1−cos2x 1+cos2x) Q. Integrate ∫ tan−1(√ 1−cos2x 1+cos2x)dx. Q. The minimum integral value of x for which 2x2+2x+n>9+sin−1(sin(−1))+cos−1(cos(−1)) ∀x∈R, is. Q. Integrate the following: 1 √1+cos2x. Q. Integrate : ∫ 1 1−cos2xdx. View More.Precalculus. Solve for ? cos (x)^2-1=0. cos2 (x) − 1 = 0 cos 2 ( x) - 1 = 0. Add 1 1 to both sides of the equation. cos2(x) = 1 cos 2 ( x) = 1. Take the specified root of both sides of the equation to eliminate the exponent on the left side. cos(x) = ±√1 cos ( x) = ± 1. Any root of 1 1 is 1 1. cos(x) = ±1 cos ( x) = ± 1.Now, that we have derived cos2x = cos 2 x - sin 2 x, we will derive cos2x in terms of tan x. We will use a few trigonometric identities and trigonometric formulas such as cos2x = cos 2 x - sin 2 x, cos 2 x + sin 2 x = 1, and tan x = sin x/ cos x.Develop the left side: #LS = (cos^2 x)/(sin^2 x) - cos ^2 x = ((cos^2 x)(1 - sin^2 x))/(sin^2 x) =# #= (cos^2 x.cos^2 x)/(sin^2 x) = cot^2 x.cos^2 x# Proved.It is indeed true that sin2(x)= 1 −cos2(x) and that sin2(x)= 21−cos(2x). How do you use the half-angle identities to find all solutions on the interval [0,2pi) for the equation sin2x = cos2(2x) ? 3π,π and 3.5π Explanation: Use cos2a = 2cos2a−1 . The given equation is sin2x = 1−cos2x = 1−(2cos2(2x)−1)2 = cos2(2x) ...cos(2x) = cos 2 (x) − sin 2 (x) = 1 − 2 sin 2 (x) = 2 cos 2 (x) − 1 Half-Angle Identities The above identities can be re-stated by squaring each side and doubling all of the angle measures.This simplifies to sinx. Use sin^2theta + cos^2theta = 1 -> sin^2theta = 1- cos^2theta and csctheta = 1/sintheta. =(sin^2x)(cscx) = (sin^2x)(1/sinx) = sinx Hopefully this helps!x^{2}-x-6=0-x+3\gt 2x+1; line\:(1,\:2),\:(3,\:1) f(x)=x^3; prove\:\tan^2(x)-\sin^2(x)=\tan^2(x)\sin^2(x) \frac{d}{dx}(\frac{3x+9}{2-x}) (\sin^2(\theta))' \sin(120) \lim _{x\to 0}(x\ln (x)) \int e^x\cos (x)dx \int_{0}^{\pi}\sin(x)dx \sum_{n=0}^{\infty}\frac{3}{2^n} Show More Evaluate the integral. ∫ ( cos 2 x - 1) ( cos 2 x + 1) d x. = – ∫ ( 2 sin 2 x) ( 2 cos 2 x) d x = – ∫ tan 2 x d x = ∫ ( 1 – s e c 2 x) d x = x – tan x + C.This simplifies to sinx. Use sin^2theta + cos^2theta = 1 -> sin^2theta = 1- cos^2theta and csctheta = 1/sintheta. =(sin^2x)(cscx) = (sin^2x)(1/sinx) = sinx Hopefully this helps!You don't have to memorize all formulas but it helps to do so. If you remember, 1 = cos^2 x + sin^2 x. So we have, cos^2 x = 1 - sin^2 x and sin^2 x = 1 - cos^2 x. If we replace cos^2 x in the first double angle formula cos2x = cos^2 x - sin^2 x with 1 - sin^2 x we get: cos2x = 1 - 2 sin^2 x.Ratnaker Mehta. Sep 2, 2016. ∫ 1 (cosx)2 dx = ∫sec2xdx = tanx + C. Answer link.We would like to show you a description here but the site won’t allow us.1 Answer (s) Available. Find the integration of the expression as per attachment. 1 Answer (s) Available. Integrate whole root of x- alpha/ beta - alpha lower limit =alpha and upper limit = beta. 1 Answer (s) Available.Jan 23, 2017 · 🏼 https://integralsforyou.com - Integral of 1/(1+cos^2(x)) - How to integrate it step by step using the substitution method!🙈 𝐒𝐚𝐦𝐞 𝐢𝐧𝐭𝐞𝐠𝐫𝐚𝐥, ?... Answer: Step-by-step explanation: Verify the Identity Cos x + cos x cot^2 x = cot x csc x 4 steps Answer choices: Cos x sec^2 x Cos x (1 + cot x) Cos x / sin x • 1 / sin x Cos x • 1 / sin^2 x Cos x (1 + cot^2 x) Cos x csc^2 xsin(2X) = 2 sinX cosX cos(2X) = 1 - 2sin 2 X = 2cos 2 X - 1 tan(2X) = 2tanX / [ 1 - tan 2 X ] Multiple Angle Formulas sin(3X) = 3sinX - 4sin 3 X cos(3X) = 4cos 3 X - 3cosX sin(4X) = 4sinXcosX - 8sin 3 XcosX cos(4X) = 8cos 4 X - 8cos 2 X + 1Jul 21, 2023 · Step by step video solution for int(1+ cos^2(x))/(1+cos(2x))dx by Maths experts to help you in doubts & scoring excellent marks in Class 12 exams. Ab Padhai karo bina ads ke Khareedo DN Pro and dekho sari videos bina kisi ad ki rukaavat ke! Dec 2, 2018 · In this video, we are going to derive value of 1 - cosine of 2x.The identity cos(2x) has been explained in the following videohttps://youtu.be/NTgX1EY6Poo#co... Hint: cos(2x) = cos(x+x)= cosxcosx−sinxsinx= cos2x−sin2x= cos2x−(1−cos2x)= 2cos2x−1 So, cos2x= 21+cos(2x) which can be substituted. For which a ∈ R are sin2(ax),cos2(x) and 1 linear independent. You have sin2(x)= (1−cos(2x))/2 and cos2(ax) =(1+cos(2ax)/2. Hence the span of the three functions is the same as the span of 1, cos(2ax ...x^{2}-x-6=0-x+3\gt 2x+1; line\:(1,\:2),\:(3,\:1) f(x)=x^3; prove\:\tan^2(x)-\sin^2(x)=\tan^2(x)\sin^2(x) \frac{d}{dx}(\frac{3x+9}{2-x}) (\sin^2(\theta))' \sin(120) \lim _{x\to 0}(x\ln (x)) \int e^x\cos (x)dx \int_{0}^{\pi}\sin(x)dx \sum_{n=0}^{\infty}\frac{3}{2^n} Show Morex^{2}-x-6=0-x+3\gt 2x+1; line\:(1,\:2),\:(3,\:1) f(x)=x^3; prove\:\tan^2(x)-\sin^2(x)=\tan^2(x)\sin^2(x) \frac{d}{dx}(\frac{3x+9}{2-x}) (\sin^2(\theta))' \sin(120) \lim _{x\to 0}(x\ln (x)) \int e^x\cos (x)dx \int_{0}^{\pi}\sin(x)dx \sum_{n=0}^{\infty}\frac{3}{2^n} Show MoreProof cos^2 (x)= (1+cos2x)/2. Proof Half Angle Formula: sin (x/2) Proof Half Angle Formula: cos (x/2) Proof Half Angle Formula: tan (x/2) Product to Sum Formula 1. Product to Sum Formula 2. Sum to Product Formula 1.Introduction to Trigonometric Identities and Equations; 7.1 Solving Trigonometric Equations with Identities; 7.2 Sum and Difference Identities; 7.3 Double-Angle, Half-Angle, and Reduction Formulas What is the value of 1+cos^2 (x)? - Quora. Something went wrong. Wait a moment and try again.Q. Integrate w.r.to x. tan−1( √1−cos2x 1+cos2x) Q. Integrate ∫ tan−1(√ 1−cos2x 1+cos2x)dx. Q. The minimum integral value of x for which 2x2+2x+n>9+sin−1(sin(−1))+cos−1(cos(−1)) ∀x∈R, is. Q. Integrate the following: 1 √1+cos2x. Q. Integrate : ∫ 1 1−cos2xdx. View More.Compute answers using Wolfram's breakthrough technology & knowledgebase, relied on by millions of students & professionals. For math, science, nutrition, history ... Explanation: Manipulating the left side using Double angle formulae. ∙ sin2x = 2sinxcosx. ∙ cos2x = cos2x − sin2x. and using sin2x +cos2x = 1 we can also obtain. cos2x = (1 − sin2x) − sin2x = 1 −2sin2x. and cos2x = cos2x −(1 − cos2x) = 2cos2x − 1. ⇒ sin2x 1 +cos2x = 2sinxcosx 1 + 2cos2x − 1 = 2sinxcosx 2cos2x. = 2 sinxcosx ...Jun 26, 2016 · From Pythagoras theorem we get: sin2x +cos2x = 1. So: sin2x = 1 − cos2x = (1 − cosx)(1 + cosx) Answer link. Solve your math problems using our free math solver with step-by-step solutions. Our math solver supports basic math, pre-algebra, algebra, trigonometry, calculus and more.Let us equate, X and Y, i.e. X = Y. So, the above formula for cos 2X, becomes. cos 2X = cos(X + X) = cos X cos X– sin X sin X. cos 2X = cos2 X–sin2 X. Hence, the first cos 2X formula follows, as. cos 2X = cos2 X–sin2 X. And for this reason, we know this formula as double the angle formula, because we are doubling the angle.Feb 10, 2017 · This simplifies to sinx. Use sin^2theta + cos^2theta = 1 -> sin^2theta = 1- cos^2theta and csctheta = 1/sintheta. =(sin^2x)(cscx) = (sin^2x)(1/sinx) = sinx Hopefully this helps! sin^2x + cos^2x = 1 the identity known is sin^2x + cos^2x = 1. this can be rearranged to give 1 - cos^2x = sin^2x. using the 'difference of two squares' identity ...Use the identity: cos (a + b) = cos a.cos b - sin a.sin b cos 2x = cos (x + x) = cos x.cos x - sin x. sin x = cos^2 x - sin^2 x = = cos^2 x - (1 - cos^2 x) = 2cos ^2 ...Trigonometry is a branch of mathematics concerned with relationships between angles and ratios of lengths. The field emerged in the Hellenistic world during the 3rd century BC from applications of geometry to astronomical studies.It is indeed true that sin2(x)= 1 −cos2(x) and that sin2(x)= 21−cos(2x). How do you use the half-angle identities to find all solutions on the interval [0,2pi) for the equation sin2x = cos2(2x) ? 3π,π and 3.5π Explanation: Use cos2a = 2cos2a−1 . The given equation is sin2x = 1−cos2x = 1−(2cos2(2x)−1)2 = cos2(2x) ...In this video I will prove cos^2(x)=(1+cos2x)/2. Course Index. What Is The Unit Circle? The Unit Circle and The Angle (Part 1 of 2) The Unit Circle and The Angle ...Compute answers using Wolfram's breakthrough technology & knowledgebase, relied on by millions of students & professionals. For math, science, nutrition, history ...It is indeed true that sin2(x)= 1 −cos2(x) and that sin2(x)= 21−cos(2x). How do you use the half-angle identities to find all solutions on the interval [0,2pi) for the equation sin2x = cos2(2x) ? 3π,π and 3.5π Explanation: Use cos2a = 2cos2a−1 . The given equation is sin2x = 1−cos2x = 1−(2cos2(2x)−1)2 = cos2(2x) ...sin(2X) = 2 sinX cosX cos(2X) = 1 - 2sin 2 X = 2cos 2 X - 1 tan(2X) = 2tanX / [ 1 - tan 2 X ] Multiple Angle Formulas sin(3X) = 3sinX - 4sin 3 X cos(3X) = 4cos 3 X - 3cosX sin(4X) = 4sinXcosX - 8sin 3 XcosX cos(4X) = 8cos 4 X - 8cos 2 X + 1Jun 25, 2018 · How do you differentiate #1+cos^2(x)#? Calculus Differentiating Trigonometric Functions Derivative Rules for y=cos(x) and y=tan(x) 1 Answer Jim G. Free math problem solver answers your algebra, geometry, trigonometry, calculus, and statistics homework questions with step-by-step explanations, just like a math tutor.Free math problem solver answers your algebra, geometry, trigonometry, calculus, and statistics homework questions with step-by-step explanations, just like a math tutor.Hint: cos(2x) = cos(x+x)= cosxcosx−sinxsinx= cos2x−sin2x= cos2x−(1−cos2x)= 2cos2x−1 So, cos2x= 21+cos(2x) which can be substituted. For which a ∈ R are sin2(ax),cos2(x) and 1 linear independent. You have sin2(x)= (1−cos(2x))/2 and cos2(ax) =(1+cos(2ax)/2. Hence the span of the three functions is the same as the span of 1, cos(2ax ...In trigonometry formulas, we will learn all the basic formulas based on trigonometry ratios (sin,cos, tan) and identities as per Class 10, 11 and 12 syllabi. Also, find the downloadable PDF of trigonometric formulas at BYJU'S. Compute answers using Wolfram's breakthrough technology & knowledgebase, relied on by millions of students & professionals. For math, science, nutrition, history ... Free trigonometric equation calculator - solve trigonometric equations step-by-step 1. Yes, cos2(x) cos 2 ( x) usually means cos(x) ⋅ cos(x) cos ( x) ⋅ cos ( x). Most other information already given here is also correct: cos2 x cos 2. . x is probably most common as shortest. (cos(x))2 ( cos. . ( x)) 2 is most clear for beginners, but not practical - it has too much brackets, that are annoying to write and obscure ...1 Answer (s) Available. Find the integration of the expression as per attachment. 1 Answer (s) Available. Integrate whole root of x- alpha/ beta - alpha lower limit =alpha and upper limit = beta. 1 Answer (s) Available. subtract 1 from both sides. tan2x+1 −1 = sec2x −1. ⇒ sec2x −1 = tan2x. Answer link.Mar 12, 2018 · Explanation: 1 cos2x − 1 = 1 − cos2x cos2x = sin2x cos2x = tan2x. Answer link. Explanation: One way to simplify this is to use the identity. sin2x +cos2x = 1. From this we can see that. sin2x = 1 − cos2x. Therefore we have. cos2x 1 − cos2x = cos2x sin2x = cot2x. Answer link.sin^2x. Rewrite sec^2x as 1/cos^2x by the identity secx = 1/cosx. =cos^2x(1/cos^2x- 1) = 1 - cos^2x Use the identity sin^2x + cos^2x = 1 solved for sin^2x to get: = sin^2x Hopefully this helps!🏼 https://integralsforyou.com - Integral of 1/cos^2(x) - How to integrate it step by step using integration by substitution!🚶 𝐒𝐭𝐞𝐩𝐬00:00 Substitution...To solve a trigonometric simplify the equation using trigonometric identities. Then, write the equation in a standard form, and isolate the variable using algebraic manipulation to solve for the variable. Use inverse trigonometric functions to find the solutions, and check for extraneous solutions.Jun 26, 2016 · From Pythagoras theorem we get: sin2x +cos2x = 1. So: sin2x = 1 − cos2x = (1 − cosx)(1 + cosx) Answer link. What are the formulae of (1) 1 + cos2x (2) 1 cos2x Get the answer to this question and access a vast question bank that is tailored for students.From Pythagoras theorem we get: sin2x +cos2x = 1. So: sin2x = 1 − cos2x = (1 − cosx)(1 + cosx) Answer link.Jul 26, 2015 · Explanation: One way to simplify this is to use the identity. sin2x +cos2x = 1. From this we can see that. sin2x = 1 − cos2x. Therefore we have. cos2x 1 − cos2x = cos2x sin2x = cot2x. Answer link. x^{2}-x-6=0-x+3\gt 2x+1; line\:(1,\:2),\:(3,\:1) f(x)=x^3; prove\:\tan^2(x)-\sin^2(x)=\tan^2(x)\sin^2(x) \frac{d}{dx}(\frac{3x+9}{2-x}) (\sin^2(\theta))' \sin(120) \lim _{x\to 0}(x\ln (x)) \int e^x\cos (x)dx \int_{0}^{\pi}\sin(x)dx \sum_{n=0}^{\infty}\frac{3}{2^n} Show More Compute answers using Wolfram's breakthrough technology & knowledgebase, relied on by millions of students & professionals. For math, science, nutrition, history ...sin^2(theta) + cos^2(theta) = 1 (Pythagorean theorem) So 1-cos^2(theta) = sin^2(theta)See full list on purplemath.com Solve your math problems using our free math solver with step-by-step solutions. Our math solver supports basic math, pre-algebra, algebra, trigonometry, calculus and more. Solve for ? cos (x)=1/2. cos (x) = 1 2 cos ( x) = 1 2. Take the inverse cosine of both sides of the equation to extract x x from inside the cosine. x = arccos(1 2) x = arccos ( 1 2) Simplify the right side. Tap for more steps... x = π 3 x = π 3. The cosine function is positive in the first and fourth quadrants. Proof cos^2 (x)= (1+cos2x)/2. Proof Half Angle Formula: sin (x/2) Proof Half Angle Formula: cos (x/2) Proof Half Angle Formula: tan (x/2) Product to Sum Formula 1. Product to Sum Formula 2. Sum to Product Formula 1.We would like to show you a description here but the site won’t allow us. Free Pre-Algebra, Algebra, Trigonometry, Calculus, Geometry, Statistics and Chemistry calculators step-by-step1 Answer. George C. Nov 15, 2015. Use cos2x +sin2x = 1 to find: 1 − cos2x sinx = sinx.simplify\:\tan^4(x)+2\tan^2(x)+1; simplify\:\tan^2(x)\cos^2(x)+\cot^2(x)\sin^2(x) Show More; Description. Simplify trigonometric expressions to their simplest form ... Here are a few examples I have prepared: a) Simplify: tanx cscx ×secx. Apply the quotient identity tanθ = sinθ cosθ and the reciprocal identities cscθ = 1 sinθ and secθ = 1 cosθ. = sinx cosx 1 sinx × 1 cosx. = sinx cosx × sinx 1 × 1 cosx. = sin2x cos2x. Reapplying the quotient identity, in reverse form: = tan2x. b) Simplify: cscβ ... 1 Answer (s) Available. Find the integration of the expression as per attachment. 1 Answer (s) Available. Integrate whole root of x- alpha/ beta - alpha lower limit =alpha and upper limit = beta. 1 Answer (s) Available.Jun 26, 2016 · From Pythagoras theorem we get: sin2x +cos2x = 1. So: sin2x = 1 − cos2x = (1 − cosx)(1 + cosx) Answer link. Simplify and combine like terms. Tap for more steps... 1−2cos(2x)+cos2(2x) 1 - 2 cos ( 2 x) + cos 2 ( 2 x)幂简约公式. 从解余弦二倍角公式的第二和第三版本得到。. 正弦. 餘弦. 其他. sin 2 θ = 1 − cos 2 θ 2 \sin ^ {2}\theta = {\frac {1-\cos 2\theta } {2}} cos 2 θ = 1 + cos 2 θ 2 \cos ^ {2}\theta = {\frac {1+\cos 2\theta } {2}} sin 2 θ cos 2 θ = 1 − cos 4 θ 8 \sin ^ {2}\theta \cos ^ {2 ...Free trigonometric equation calculator - solve trigonometric equations step-by-step Free math problem solver answers your algebra, geometry, trigonometry, calculus, and statistics homework questions with step-by-step explanations, just like a math tutor.1. verified. Simplify the first trigonometric expression by writing the simplified form in terms of the second expression. 1. 1/1-cos (x) - cos (x)/1+cos (x) ; csc (x) 2. 1/sin (x) cos (x) - cot (x) ; cot (x) 3. cos (x)/1+sin (x) + tan (x) ; cos (x) 4. tan (x) +cot (x)/sec (x) ; sin (x) verified. Prove this identity is true using trigonometric ...What is the value of 1+cos^2 (x)? - Quora. Something went wrong. Wait a moment and try again.Free math problem solver answers your algebra, geometry, trigonometry, calculus, and statistics homework questions with step-by-step explanations, just like a math tutor.We would like to show you a description here but the site won’t allow us.simplify\:\tan^4(x)+2\tan^2(x)+1; simplify\:\tan^2(x)\cos^2(x)+\cot^2(x)\sin^2(x) Show More; Description. Simplify trigonometric expressions to their simplest form ... Trigonometry. Solve for ? cos (x)=-1/2. cos (x) = − 1 2 cos ( x) = - 1 2. Take the inverse cosine of both sides of the equation to extract x x from inside the cosine. x = arccos(−1 2) x = arccos ( - 1 2) Simplify the right side. Tap for more steps... x = 2π 3 x = 2 π 3. The cosine function is negative in the second and third quadrants.
Trigonometry. Solve for x cos (2x)=-1. cos (2x) = −1 cos ( 2 x) = - 1. Take the inverse cosine of both sides of the equation to extract x x from inside the cosine. 2x = arccos(−1) 2 x = arccos ( - 1) Simplify the right side. Tap for more steps... 2x = π 2 x = π. Divide each term in 2x = π 2 x = π by 2 2 and simplify.. Benefici
1. I'm being asked to find the arc length of y = sin(x) y = sin ( x) for [0, π 2] [ 0, π 2] using M8 M 8. I've determined that y′2 =cos2 x y ′ 2 = cos 2 x. So, using the formula for arc length, I get 1 +cos2 x− −−−−−−−√ 1 + cos 2 x as my function. Now, they want me to evaluate this using M8 M 8, so I end up with 8 8 ...Mar 12, 2018 · Explanation: 1 cos2x − 1 = 1 − cos2x cos2x = sin2x cos2x = tan2x. Answer link. You don't have to memorize all formulas but it helps to do so. If you remember, 1 = cos^2 x + sin^2 x. So we have, cos^2 x = 1 - sin^2 x and sin^2 x = 1 - cos^2 x. If we replace cos^2 x in the first double angle formula cos2x = cos^2 x - sin^2 x with 1 - sin^2 x we get: cos2x = 1 - 2 sin^2 x. Aug 16, 2016 · If n > 1 is a positive integer, then: cos^n x = (cos x)^n This is a convenience of notation, to avoid having to use parentheses to distinguish, for example: (cos x)^2 and cos (x^2) By convention we can write: cos^2 x and cos x^2 respectively, without ambiguity. However, in the case of -1, we have a clash of notation. Develop the left side: #LS = (cos^2 x)/(sin^2 x) - cos ^2 x = ((cos^2 x)(1 - sin^2 x))/(sin^2 x) =# #= (cos^2 x.cos^2 x)/(sin^2 x) = cot^2 x.cos^2 x# Proved.It is indeed true that sin2(x)= 1 −cos2(x) and that sin2(x)= 21−cos(2x). How do you use the half-angle identities to find all solutions on the interval [0,2pi) for the equation sin2x = cos2(2x) ? 3π,π and 3.5π Explanation: Use cos2a = 2cos2a−1 . The given equation is sin2x = 1−cos2x = 1−(2cos2(2x)−1)2 = cos2(2x) ...Evaluate the integral. ∫ ( cos 2 x - 1) ( cos 2 x + 1) d x. = – ∫ ( 2 sin 2 x) ( 2 cos 2 x) d x = – ∫ tan 2 x d x = ∫ ( 1 – s e c 2 x) d x = x – tan x + C. $\int \frac {1}{\cos^2 x}\,dx=\int \sec^2 x=\tan x +c$ based directly on the list of immediate integrals. The other day a student asked me if we can evaluate the integral using a method like integration by substitution or integration by parts. The only 'solution' I found uses the differentiation of quotient working backwards. I.e.To solve a trigonometric simplify the equation using trigonometric identities. Then, write the equation in a standard form, and isolate the variable using algebraic manipulation to solve for the variable. Use inverse trigonometric functions to find the solutions, and check for extraneous solutions.What are the formulae of (1) 1 + cos2x (2) 1 cos2x Get the answer to this question and access a vast question bank that is tailored for students.The expression 1 + cos 2x + cos 4x + cos 6x is equivalent to. NCERT Solutions. NCERT Solutions For Class 12. NCERT Solutions For Class 12 PhysicsMar 12, 2018 · Explanation: 1 cos2x − 1 = 1 − cos2x cos2x = sin2x cos2x = tan2x. Answer link. Jun 26, 2016 · From Pythagoras theorem we get: sin2x +cos2x = 1. So: sin2x = 1 − cos2x = (1 − cosx)(1 + cosx) Answer link. .