What is the derivative of y=arcsin(x/7)?

1 Answer
Apr 16, 2018

d/dx arcsin(x/7)=(\sqrt{49-x^2})^{-1}

Explanation:

We want to evaluate d/dx arcsin(x/7).

We can apply the chain rule, that (f@g)'(x)=(f'@g)(x)g'(x), and in our case f=arcsin and g(x)=1/7x. Therefore:

d/dx arcsin(x/7)=\frac{1}{\sqrt{1-x^2/7^2}}\cdot d/dx x/7

d/dx arcsin(x/7)=\frac{1/7 d/dx x}{\sqrt{1-x^2/7^2}}

d/dx arcsin(x/7)=\frac{1}{7\sqrt{1-x^2/49}}

We can further simplify this:

d/dx arcsin(x/7)=\frac{1}{\sqrt{49(1-x^2/49)}}

d/dx arcsin(x/7)=(\sqrt{49-x^2})^{-1}