Question

Express all trignometric ratios in terms of cos

Answer 1

cos x 
sin x = √(1 – cos² x) 
tan x = sin x/cos x = (√(1 – cos² x))/cos x 
cot x = cos x/sin x = cos x/√(1 – cos² x) 
sec x = 1/cos x 
csc x = 1/sin x = 1/√(1 – cos² x)

Answers

Acos(x) + B sin(x) = (√(A^2 + B^2))cos(x - tan^-1(B/A)) cos(x) - sin (x) = (√2)cos(x + π/4)

Answer 2

cos theta

0 degree= 1
30 degree=root3 /4
45 degree= 1/root 2
60 degree= 1/4
90 degree= 0

I hope this will help you