The power rule says that (d/dx)(x^n)=nx^{n-1}.

Use the power rule with n=INT.

It says (d/dx)(x^INT)=INTx^{INT-1}.

Now you just have to compute that exponent: k=INT-1.

Then, in the "Answer" box, you type in:
                 INTx^k
but be sure to replace k by the number that you computed.