Question #a5f39

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1 Answer
mason m
Oct 3, 2017

#sec^4(x)+C#

Explanation:

#int4sec^4(x)tan(x)dx#

#=4intsec^3(x)[sec(x)tan(x)dx]#

Let #u=sec(x)#. Differentiating shows that #du=sec(x)tan(x)dx#, which is already in the integrand.

#=4intu^3du#

#=4(u^4/4)+C#

#=sec^4(x)+C#

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