In this question, `f(t) = t sin(t^t)`
So the derivative is just:
`d/dx int_m^x t sin(t^t)dt = x sin(x^x)`
We haven't learned to integrate cases like `int_m^x t sin(t^t)dt`, but we don't need to know how to do it. (Actually, this integral is impossible using ordinary functions, but we can find its derivative easily.)
Note the constant `m` doesn't make any difference to the final derivative.