# trig

2. ### not sure what to do

cos^2(18) - sin^2(18)
3. ### Finding solutions of an equation

Find all of the solutions of the equation cos(56°-3x)=-0.785 where 0° ≤ x ≤ 360° I've been able to find one soloution using x = (56 - arccos(-0.785)) / 3. But I'm unable to find any others. Thanks in advance for any help
4. ### Requesting guidance on Algebra-2 problems

Hello everyone. Attached are 2 pictures of the math i need help on. I already have the answer key. What I need are the steps/work. If you could post a picture with your steps written on paper that would be much appreciated. Even if you only know a few, anything helps. thank you, Peyton
5. ### Trigonometric Ratios

Hi, I hope someone can help. The question that I'm working on is 3c: I currently see there being two methods towards solving this question. I need guidance on which method is the correct one, and explaining why this the correct method. Method 1 - I use my calculator. For example, sin(7pi/4)...
6. ### Trig and Calculus:

The textbook I used didn't provide a detailed enough explanation. How should I approach this problem? Thank you in advance! :)
7. ### Having trouble with proving a trig identity

Hi, I'm working on a trigonometry unit at the moment, and after going through the current lesson several times I still feel like I'm missing some things. I'm working on proving an identity right now that has me stumped, I tried resorting to using an online solver but in the steps it is telling...
8. ### Pilot and wind velocity vector help

A pilot needs to fly 35 degrees east of north. He's flying at a speed of 105 miles per hour at fixed altitude with no wind. When he reaches a point, he encounters wind with a velocity of 15 miles per hour in the direction 10 degrees east of north. Express the velocity of the wind W as a vector...
9. ### Trig equation over specified interval

2sin(x-7) + 6 = cos(2x-10) + 8 Solutions in [6,14] I don't even know where to begin. If there wasn't a constant I would set it to 0 and try sum to product then find zeros. Then there's dealing with the applied interval. Ken T. Also did a rough sketch to make sure it wasn't a trick...
10. ### integration of trig function

Integrate sin(wt)sin(wt+s) Answer: (1/2)tcos(s) - (1/4w)sin(2wt+s)+c I would appreciate even a tip of how to start it correctly. I tried a lot to do this, but I can't find the correct answer.
11. ### Find Fourier coefficients of g(x) = f(2x)

Hi, I have the following problem: Assume that the function is -periodic and has the Fourier series: Find the Fourier coefficients of the function g(x) = f(2x) As far as I understood, the Fourier coefficients of this function can not be a number, because we don't have the function...
12. ### New to the forum and crappy at Trig.

If anyone can help me with a few trig questions I would really appreciate it. Private message me please . I am desperate. Jeryan
13. ### Some questions to do with trig identities (I think)

I have no idea how to do this stuff so here I am. I need to simplify these three problems: sin^2θ+sec^2θ+tan^2θ+cos^2θ x+sin^2xsecx (cscx+1)(cscx-1)

Evaluate the expression under the given conditions. tan(θ+φ) given cosθ = -1/3 in Q3 and sinφ = 1/4 in Q2 I'm not really sure where to begin. Thanks in advance.
15. ### Need trig help?

I take all of my classes online, so I don't have the opportunity for in class help and this is really kicking up my anxiety, because I'm not understanding anything about this, or any of the concepts. 1. Your family rents cottage on the ocean for a week one summer. you notice that the tide...
16. ### Trig substitution

Whitman 8.3.6 $\displaystyle I= \int x^2 \sqrt{1-x^2 } \ dx = \arcsin\left({x}\right)/8-\sin\left({4\arcsin\left({x}\right)}\right)/32+C$ As given by book answer. $$x=\sin\left({u}\right)\ \ \ dx=-\cos\left({u}\right) \ du$$ so then \displaystyle I=\int\sin^2 \left({u}\right) \cos^2...
17. ### What is this odd looking symbol I found in my 10th ed.lial and hornsby trig book?

I was reading through my lial and hornsby trigonometry book and in section 3.2 I came across a new symbol. I looked across all of the greek alphabet and none of them are quite similar enough for me to come to the conclusion that they are the same letter I'm looking at. I don't expect it to be a...
18. ### Trig angle Formulas

Hey, I am confused as to how to break down this question. "Evaluate using formulas developed in this section." a) sin 11pi/12 the formulas are the addition and subtraction as well as double angle formulas. i know that 11pi/12 = pi/3 + pi/4 + pi/4 + pi/6 but am not sure how to turn it into a...
19. ### Integration of Inverse Trig Functions 2

I am having trouble integrating the function below. I haven't studied integration techniques beyond integration by substitution and a few basic integration tables. So, do not show integration by parts, trigonometric substitution or partial fractions in terms of solving this problem. I think...
20. ### Integration of Inverse Trig Functions 1

I am having trouble integrating the function below. I haven't studied integration techniques beyond integration by substitution and a few basic integration tables. So, do not show integration by parts, trigonometric substitution or partial fractions in terms of solving this problem. I think...