We have the function g(x) = sin 9x.

We have to find the second derivative of g(x). We use the chain rule here.

g(x) = sin 9x

=> g'(x) = 9 cos 9x

=> g''(x) = -81 sin 9x

**The required second derivative is -81 sin 9x**

We have the function g(x) = sin 9x.

We have to find the second derivative of g(x). We use the chain rule here.

g(x) = sin 9x

=> g'(x) = 9 cos 9x

=> g''(x) = -81 sin 9x

**The required second derivative is -81 sin 9x**