Question

The value of cos-1x+sin-1x=?

Answer 1

Answer:

Given, cos

−1

(x)>sin

−1

(x)

cos

−1

(x)>

2

π

−cos

−1

(x) ....... [∵sin

−1

x+cos

−1

x=

2

π

]

2cos

−1

(x)>

2

π

cos

−1

(x)>

4x<cos( 4π ) ...(cosθ is a decreasing function)

x< 21

Now, we know that the domain of cos

−1

is [−1,1]

Hence, xϵ[−1, 21 ]