Evaluate the Integral
Problem
Solution
Identify the integral as a non-elementary integral. The function
ƒ(x)=e(x2)/2 does not have an antiderivative that can be expressed in terms of basic functions like polynomials, logarithms, or trigonometric functions.Relate the integral to the imaginary error function,
erfi(z) which is defined aserfi(z)=2/√(,π)*(∫_0^z)(e(t2)*d(t)) Perform a substitution to match the standard form. Let
u=x/√(,2) which impliesx=u√(,2) andd(x)=√(,2)*d(u) Substitute these into the integral to get
(∫_^)(e(u2)√(,2)*d(u)) Apply the definition of the imaginary error function, where
(∫_^)(e(u2)*d(u))=√(,π)/2*erfi(u)+C Back-substitute
u=x/√(,2) to find the final expression.
Final Answer
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