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the indefinite integral of cos^2(x) * sin(x)

2007-06-29 13:03:42 · 5 answers · asked by howie 2 in Science & Mathematics Mathematics

5 answers

this is a very simple integral.
the answer is - (cos x) ^3 / 3 + C. You can arrive at that answer by taking u to be cos x, hence du = - sin x dx. And you change the integral to the integral of a monomial in u. Once you integrate in u, switch back to x.

2007-06-29 13:12:35 · answer #1 · answered by Anonymous · 0 0

It's a substitutionl

Let U=cos(x)
dU=-sin(x)

then

Int(-U^2)du = -U^3/3=-cos(x)^3/3

2007-06-29 20:12:40 · answer #2 · answered by Shawn A 3 · 0 0

integral cos^2(x)(sin(x)) dx
make u=cos (x) and du= -sinx(x) dx
therefore it becomes integral -u^2 du
take the integral and you get -u^3/3 +C
substitute back in you get -(cos^3(x)/3) + C

2007-06-29 20:16:00 · answer #3 · answered by energystar 1 · 0 0

You need to use a u-substitution. Let u = cos(x), then
du = -sin(x) dx. Thus you get:
int(cos^2(x)*sin(x) dx)
= - int(cos^2(x)*(-sin(x)) dx)
= - int(u^2 du)
= - u^3/3 + c
= - cos^3(x)/3 + c
Hope this helps.

2007-06-29 20:17:21 · answer #4 · answered by Lee 3 · 0 0

I = ∫ cos ² x.sinx.dx
let u = cos x
du = - sin x.dx
I = - ∫ u ² du
I = - u ³ / 3 + C
I = (- cos ³ x) / 3 + C

2007-07-03 14:41:11 · answer #5 · answered by Como 7 · 0 0

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