(1 point) Using the method of substitution, 1 = 1/ x' (1 + 2x2)3 dx = / f(u)du where u = (1+2x^2)13 du = dx f(u) = Using the above information: x' ( 1 + 2x 2 ) 'dx = / f(u)du = (in terms of u) (in terms of x)