Question

What is the value of Cos(2Cos-1x+Sin-1x) at x=1/5?

Answer 1

Answer:

cos-1x + sin-1x = pi/2   _________1                   (identity)

cos(2cos-1x+sin-1x) = cos[(cos-1x+sin-1x) + cos-1x]

=cos[pi/2 + cos-1x]                             (by using eq 1)

(we know , cos[pi/2+A] = -sinA)

 

=-sin[cos-1x]

=-sin[sin-1(1-x2)1/2]                              (cos-1x = sin-1(1-x2)1/2  )

=-(1-x2)1/2  

at x = 1/5  

=-(2root6)/5

FOLLOW MEH!

Step-by-step explanation: