Attachment 18445

there is no numerator... now i'm confused. i know i use the trig sub is x=a tan theta

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- Aug 4th 2010, 08:24 PMsoftballchicktrig substitution
Attachment 18445

there is no numerator... now i'm confused. i know i use the trig sub is x=a tan theta - Aug 4th 2010, 08:29 PMAlso sprach Zarathustra
sqrt(x^2+2x)=sqrt(x^2+2x+1-1)=sqrt((x+1)^2-1)

sub: t=x+1

sqrt(t^2-1)

sub: t=sec(k)

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. - Aug 4th 2010, 09:13 PMsoftballchick
ok so I get

sqrt(sec^2(k)-1)d theta

t=sec(k)

so dt is the derivative of sec? - Aug 4th 2010, 11:33 PMProve It
Hyperbolic substitution is easier in this case than trigonometric...

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Now let so that and the integral becomes

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