Definite Integral of a Trig Fxn

johnhuntsman
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π/3
∫tan^5 x sec x
0

I want to split the tan^5 x into a (sec^2 x - 1) but I only have sec x. So I'm a bit stuck. Help is appreciated.
 
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Bring the integral in the form ∫f(cos(x))sin(x)dx.

ehild
 
johnhuntsman said:
π/3
∫tan^5 x sec x
0

I want to split the tan^5 x into a (sec^2 x - 1) but I only have sec x. So I'm a bit stuck. Help is appreciated.
Finding the anti-derivative of tan5(x) sec(x) is a lot like solving your previous tread.

Split tan5(x) into tan4(x) tan(x) then use the trig identity which will change tan4(x)  into a combination of secant functions.
 
^ That did the trick. Thank you : D
 
Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...
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