Hey forum how would I go about in order to compute this indefinite integral,

I can't seem to eliminate all -variables using . I know I can simply compute it by expanding the integrand but I want to do it using substitution in particular.

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- Jul 29th 2012, 10:27 AMSweatingBearIntegrating (x² + 1)² using substitution
Hey forum how would I go about in order to compute this indefinite integral,

I can't seem to eliminate all -variables using . I know I can simply compute it by expanding the integrand but I want to do it using substitution in particular. - Jul 29th 2012, 10:42 AMjeduhiRe: Integrating (x² + 1)² using substitution
Nevermind, my answer only works for 1 over your problem

- Jul 29th 2012, 10:43 AMProve ItRe: Integrating (x² + 1)² using substitution
- Jul 29th 2012, 11:14 AMMathCrusaderRe: Integrating (x² + 1)² using substitution
- Jul 29th 2012, 11:27 AMProve ItRe: Integrating (x² + 1)² using substitution
I'll rephrase that. You can't perform a u substitution, because doing so requires the substituted function's derivative being a factor of your integrand. If you let u = x^2 + 1, then you need to have a factor of 2x in your integrand as well. You don't, so you can't use u substitution.

You could possibly use a trigonometric or hyperbolic substitution, but doing so is time consuming and pointless, when a perfect square is quick and easy to expand and the resulting integrand easy to integrate using the power rule.