Math/trig
posted by Dre .
Solve the equation in the given Domain:
1cos theta/ sin theta = sqr3, 0degrees <or equal to theta < 369 degrees
cos4x + cos 2x =0, 0<or equal to x < pi

Recall that
1cos theta/ sin theta = tan(theta/2)
so, we want tan(theta/2) = sqrt(3)
theta/2 = 60
theta = 120
Note that theta/2 = 240 also works, but that requires theta=480, outside the domain given.
___________________________
2cos^2(2x)  1 + cos(2x) = 0
(2cos2x  1)(cos2x + 1) = 0
cos2x = 1/2, so 2x = 60,300, so x=30,150
cos2x = 1, so 2x = 180, so x=90
Respond to this Question
Similar Questions

Trig
Which expression equivalent to: cos(theta + pi/2). A)cos theta B)cos theta C)sin theta D)sin theta my book doesnt give examples of this but my crack at it would be C b/c distributive property? 
Algebra II
Which of the following expressions are not equal to 1? 
Calculus
I wanted to confirm that I solved these problems correctly (we had to convert the polar curves to Cartesian equations). 1.rcos(theta)=1 x=1 2.r=2*sin(theta)+2*cos(theta) r^2=2rsin(theta)+2rcos(theta) x^2+y^2=2y+2x (a little unsure … 
Precalculs
I have no idea how to do these type of problems. Problem Solve each equation on the interval 0 less than or equal to theta less than 2 pi 42. SQRT(3) sin theta + cos theta = 1  There is an example … 
Precalculus(NEED HELP ASAP PLEASE!!)
Solve: sin(theta)cos(theta)sin(theta)−cos(theta)+1 = 0, 0 < or equal to theta < 2pi Solution Set: ____________ ? 
trig
Hi, I need to find the domain and rnge of the following: 1. X= 1/2 (cos theta + theta sin theta) Y=1/2 (sin theta  theta cos theta) total guess here, but here goes Domain cos theta = +/ 1 and domain sin theta = +/ 1 so domain theta … 
Trigonometry
Thank you STEVE!!!!! Suppose that Cos (theta) = 1/square root 2 if 0<equal to theta , pi/2 then sin(theta) = tan (theta) = If 3pi/2 less than equal to theta , 2pi then sin(theta) = tan (theta) = I know the trig functions but I feel … 
trig
If sin theta is equal to 5/13 and theta is an angle in quadrant II find the value of cos theta, sec theta, tan theta, csc theta, cot theta. 
Math Trig Help
sin theta = x/3, with theta in the first quadrant, find the expression for cos theta and tan theta. Answers will be in algebraic terms of x. Give exact answers with 0 < theta <pi/2 (0 less than or equal to theta, less than or … 
Precalculus
Circle O below has radius 1. Eight segment lengths are labeled with lowercase letters. Six of these equal a trigonometric function of theta. Your answer to this problem should be a six letter sequence whose letters represent the segment …