math

What is under the square root?

I think there are likely other errors in there as well.

Please check your question carefully.

Or maybe write the equation without latex? because some latex doesn't seem to show and most latex under square roots don't show here. I tried it before. 

If @OP didn't use latex, then I guess the equation would be: f(x) = arctan(cosx)/arcsin(1-2xsqrtf'(0)