Calculus 2: trying to intergrate 6sec^3 dx

CajunHoss87

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Hi I'm trying to intergrate 6sec^3 dx and I'm having trouble.

I have 6integral (tanx^2+1)*secx dx but I am stuck.

What do I do?
 
Re: Calculus 2

sec3(x)dx\displaystyle \int sec^{3}(x)dx

We can just use the general reduction formula:

secn(x)dx=secn2(x)tan(x)n1+n2n1secn2(x)dx\displaystyle \int sec^{n}(x)dx=\frac{sec^{n-2}(x)tan(x)}{n-1}+\frac{n-2}{n-1}\int sec^{n-2}(x)dx
 
Re: Calculus 2

CajunHoss87 said:
Hi I'm trying to intergrate 6sec^3 dx and I'm having trouble.

I have 6integral (tanx^2+1)*secx dx but I am stuck.

What do I do?

sec3(x)dx=tan(x).sec(x)tan2(x).sec(x)dx=tan(x).sec(x)[sec2(x)1].sec(x)dx\displaystyle \int \sec^3(x) dx=\tan(x).sec(x) -\int tan^2(x).sec(x)dx=tan(x).sec(x) - \int[sec^2(x)-1].sec(x)dx

sec3(x)dx=12[tan(x).sec(x)+ln[sec(x)+tan(x)]]\displaystyle \int \sec^3(x) dx \, = \, \frac{1}{2}[tan(x).sec(x) + ln[|sec(x)+tan(x)|]]
 
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