Question
Use either substitution or integration by parts to evaluate the integral:
∫(x+2)/(x²+2) dx
Thank you!!
∫(x+2)/(x²+2) dx
Thank you!!
Answers
If x = √2 tan t,
x<sup>2</sup> = 2tan<sup>2</sup>t
x<sup>2</sup> + 2 = 2sec<sup>2</sup>t
dx = √2 sec<sup>2</sup>t
and the integrand becomes
(√2 tan t + 2)/(2sec<sup>2</sup>t) * √2 sec<sup>2</sup>t
= (√2 tan t + 2)/√2 = tan t + √2
Play around with that, remembering that d(cost) = -sint
x<sup>2</sup> = 2tan<sup>2</sup>t
x<sup>2</sup> + 2 = 2sec<sup>2</sup>t
dx = √2 sec<sup>2</sup>t
and the integrand becomes
(√2 tan t + 2)/(2sec<sup>2</sup>t) * √2 sec<sup>2</sup>t
= (√2 tan t + 2)/√2 = tan t + √2
Play around with that, remembering that d(cost) = -sint
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