
Derivative of sin-1x
Let y = sin-1 x, then sin y = x.


Derivative of cos-1x


Hence, we have

Derivative of tan-1x
Let y = tan-1x. Then tan y = x.
Differentiating both sides w.r.t. x, we get

Derivative of cot-1x



Derivative of sec-1x
Let y = sec-1x. Then sec y = x.
Differentiating w.r.t. x, we have

Similarly,

Example 1:

Suggested answer:
Let
Differentiating with respect to x, we get


Example 2:
Differentiate cos-1(2x+3) from first principles.
Suggested answer:
Let y = cos-1(2x+3)
2x + 3 = cos y ……….(1)Let Dx be an increment of x and Dy be the corresponding increment of y.
Therefore 2(x + Dx) + 3 = cos (y + Dy)2x + 2Dx + 3 = cos (y + Dy) ……….(2)
Subtracting (1) from (2), we have2x + 2Dx + 3 - 2x - 3 = cos (y + Dy) - cosy

Using the formula,





