Question

If sinA,cosA & tanA are in GP find the value of cos^3A + cos^2A

Answer 1

cosa/sina=tana/cosa
cos^2a =tana×sina
cos^2a=sin^2a/cosa
cos^3a=sin^2a
cos^3a+cos^2a=sin^2a+cos2^a
cos^3a+cos^2a=1

Answer 2

Answer:

1

Step-by-step explanation:

the equation that is applicable in gp is

b^2 = a*c

here we have cosA as b

therefore,

cos^2A = sinA*tanA

             = sinA*sinA/cosA              (writing tan as sinA/cosA)

we get :

cos^3A= sin^2A

thus,

substituting the value in the question , we get :

sin^2A + cos^2A  = 1

thus

the answer is 1.