Integral of a base to a quadratic: .
Since we know the integral , we should try a substitution for the exponent:
Let . Then .
Hence the combination in the original problem is .
Now we substitute and use the Scalar Multiple Rule for integrals:
Now we use the integral for the exponential of a general base:
Finally, we substitute for u to get the result in terms of x:
Notice that the exponent in the resulting function is the same as that in the original problem.