# cos

1. ### Integral of sin x cos2 x sin(cos x) dx

I need to calculate the integral of sin(x)cos2(x)sin(cos(x)) dx (without specific boundaries) but I'm struggling with this one. Can someone help me?
2. ### Integral of (cosx+sinx)^2dx

I did this but not sure if it is correct: ∫(cosx+sinx)^2dx= ∫(cos^2x+2cosxsinx+sin^2x)= ∫(2cosxsinx)= 2∫cosxsinx= 2sinx-cosx+C <--------End
3. ### 2 equations 2 unknowns

Please help me understand step by step how to solve this problem. I have 2 formula's with 2 unknows: 0.4*cos(a) - 0.3*cos(b) = 0.49 0.4*sin(a) - 0.3*sin(b) = -0.04 I have tried allot of things but i can't solve the problem :-( The teacher has given me the answer, so i can check that i get it...
4. ### Cos A=-1/2

How can I compute that A= 120 degress if Cos A = -1/2?
5. ### cos x + sin x = 2x

I have two questions I can't figure out. 1. Solve on the interval 0 <= theta < 2pi 3 cot^2 theta - 4 csc theta = 1 2. Says solve using a calculator on the same interval. Round to two decimals. Cos x + sin x = 2x
6. ### solve cos z = cosh z in complex numbers

Can someone help with this? Wolfram Alpha gives solution but I don't know how they come up with it. I know cosh z = cos iz and cosh iz = cos z but that doesn't help me here.
7. ### 4 positive real-number values of t for which cos t=0

List four positive real-number values of t for which cos t=0 So we know that cosine is the x-axis. So cosine at 0, and they want me to list four positive real number values? So It could be 0,0 , 0, pi/2, 0,pi , and 3pi/2 The answer in the book has pi/2, 3pi/2, 5pi/2, 7pi/2...
8. ### sine cos and tan waves

not to sure weather this is in the right section bbut please i really dont understand how to do it. q= 44 Task 2a Sketch the function y = A sin (Ө) over one complete cycle, at 30o intervals, where A = q/10. State the amplitude. Task 2b Sketch the function y = cos...
9. ### proof sin-theta=-sin theta and cos (-theta)=cos theta

Can someone give me proof for sin(-theta)= - sin theta and cos(-theta)=cos theta?
10. ### hypotenuse, adjacent, opp for cos 90+theta or sin 90 + theta.

How do you choose hypotenuse, opposite and adjacent side for cos 90+theta or sin 90 + theta in a circle? Similarly for sin 180- theta or cos 180 - theta in a circle.
11. ### lim (cos x )^(1/x ) when x = 0

here's my working , is it correct ?
12. ### Trig integration with even sin and cos

Hi, I was working on a trig integration problem. And I got stuck on a step. I am attaching my work so far please let me know if it is correct so far and how to complete the problem. Or if there is a better way to solve this please suggest it thanks! Thanks!
13. ### How do I prove/disprove: (sinx + sin 5x)/(cosx + cos 5x) ≟ tan3x

(sinx + sin 5x)/(cosx + cos 5x) ≟ tan3x
14. ### IVT and Cos

Use the Intermediate Value Theorem to show that there is a root of the given equation in the specified interval. 1). cos x = x. (0,1) 2) sin x = x^2 -x. (1,2) I'm confused by the equations. Don't you take sin and cos of an angle in radians? How can cos x = x? How would I solve the problems?
15. ### Show that (1/cosΘ) - cos Θ = sin Θ tan Θ

Show that (1/cosΘ) - cos Θ = sin Θ tan Θ
16. ### Trig , sin , cos

x=l1*cos(a)+l2*cos(b) y=l1*sin(a)+l2*sin(b) Given x,y,l1,l2 Calculate a , b can you tell me how to calculate that ?
17. ### Geometric Series Cos

The question I'm looking at is: \sum_{n=1}^\infty \frac{cos\left(n\pi\right)}{2^n} Find if converge or diverge and if converge find the sum. The only things I have learned so far about series is the nth term test and geometric series. So my first attempt is to is if it diverges using the nth...
18. ### Sin 90 + theta = cos theta.

Can someone show me the proof of sin 90 + theta = cost theta in a unit circle. Thanks!
19. ### Computing sin and cos

Hi there, My task is writing an algorithm to calculate sin and cos(theta) based on a technique. I think i'll be able to handle the programming side, my issue is in understanding what it is exactly the program needs to do. As I understand it, the x and y coordinates for a particular angle...
20. ### Trigonometric Identities

Need help understanding the question: If sin t=c, 0 < t < pi/2, find in terms of c: (a) sin(pi-t) (b) cos(-t) Do I need to use this type of function?: sin(a-b) = sin(a)cos(b) - cos(a)sin(b) And how would state my answer that it is 0 < t < pi/2 Thanks