I'm trying to differentiate 2^(x^2), but I'm getting a factor of two out and can't figure out why. I approached the question as follows.. y=2^(x^2) , so y=(2^x)^x u=2^x y=u^x du/dx = (2^x)ln2 dy/du = xu^(x-1) = x(2^x)^(x-1) = x(2)^((x^2)-x) So dy/dx = [x(2)^((x^2)-x)]*[(2^x)Ln2] However, on the mark scheme it says when x=2, the gradient should be 64ln2. Using my derivative, at x=2 the gradient comes out at 32ln2. Can anyone help me find where I've gone wrong? Much appreciated!