trig
posted by Maddie .
If tan y = 4/3 and y is in Q I'VE find cos 2y

Should this be Q IV (quadrant 4)
tan1(4/3) = 53.13 degrees (53.13 degrees = 360 + 53.13 = 306.87, is in quadrant 4)
Evaluate with your calculator cos(2*306.87)
Respond to this Question
Similar Questions

trig
Show that 1cos2A/Cos^2*A = tan^2*A 1cos2A/Cos^2*A = [Cos^2(A)  Cos(2A)]/Cos^2(A). Substitute: Cos(2A) = 2Cos^2(A)  1: [1  Cos^2(A)]/Cos^2(A)= Sin^2(A)/Cos^2(A) = tan^2(A) 
Trig
Given: cos u = 3/5; 0 < u < pi/2 cos v = 5/13; 3pi/2 < v < 2pi Find: sin (v + u) cos (v  u) tan (v + u) First compute or list the cosine and sine of both u and v. Then use the combination rules sin (v + u) = sin u cos … 
Trig.
sec^2xcotxcotx=tanx (1/cos)^2 times (1/tan)(1/tan)=tan (1/cos^2) times (2/tan)=tan (2/cos^2tan)times tan=tan(tan) sq. root of (2/cos^2)= sq. root of (tan^2) sq. root of (2i)/cos=tan I'm not sure if I did this right. If I didn't, … 
trig 26
simplify to a constant or trig func. 1. sec ²utan ²u/cos ²v+sin ²v change expression to only sines and cosines. then to a basic trig function. 2. sin(theta)  tan(theta)*cos(theta)+ cos(pi/2  theta) 3. (sec y  tan y)(sec y + … 
TRIG
what is another form of: sin (A+B) sin (AB)/ cos^2 A cos^2 B a) cos^2 A  cos^2 B b) tan^2 A  tan^2 B c) tan^2 A  tan^2 B d) sin^2 A  sin^2 B please show the steps you take to get to the answer! thank you 
Trigonometry
1.Solve tan^2x + tan x – 1 = 0 for the principal value(s) to two decimal places. 6.Prove that tan y cos^2 y + sin^2y/sin y = cos y + sin y 10.Prove that 1+tanθ/1tanθ = sec^2θ+2tanθ/1tan^2θ 17.Prove that … 
precalculus
For each of the following determine whether or not it is an identity and prove your result. a. cos(x)sec(x)sin^2(x)=cos^2(x) b. tan(x+(pi/4))= (tan(x)+1)/(1tan(x)) c. (cos(x+y))/(cos(xy))= (1tan(x)tan(y))/(1+tan(x)tan(y)) d. (tan(x)+sin(x))/(1+cos(x))=tan(x) … 
trig help much appreciated! :))
1. Find the complete exact solution of sin x = . 2. Solve cos 2x – 3sin x cos 2x = 0 for the principal value(s) to two decimal places. 3. Solve tan2 x + tan x – 1 = 0 for the principal value(s) to two decimal places. 4. Prove that … 
Trigonometry desperate help, clueless girl here
2. solve cos 2x3sin x cos 2x=0 for the principal values to two decimal places. 3. solve tan^2 + tan x1= 0 for the principal values to two decimal places. 4. Prove that tan^2(x) 1 + cos^2(x) = tan^2(x) sin^2 (x). 5.Prove that tan(x) … 
Precalculus help
I have two problems I am stuck on, if you could show me how to solve the problems it would be much appreciated. 1) Find sin 2x, cos 2x, and tan 2x from the given information. tan x = − 1/6, cos x > 0 sin 2x = cos 2x = tan …