If tan(x)=2/25 (in quad 1) find the following: cos(2x)

Answer 1

Since cos 2x = cos^2-sin^2 your first task is to calculate sinx and cosx which is easily Dione since you are given tan x=2/25 so opposite =2 and adj=25 which makes the hypotenuse sqroot 629

sinx= 2/sqroot 629

cosx = 25/sqroot 629

cos^2-sin^2= 625/629 -4/629= 621/629