We have given

Let us Assume

And

So, y= cos v

Now, differentiate w.r.t v

And, v= tan w

Now, again differentiate w.r.t. w

And, we know,

So, differentiate w w.r.t. x we get

Now, using chain rule we get,

Substitute the value of v and w ,

Hence, dy/dy is the differentiation of function.