Question about where to start this trig substitution integral

In summary, the problem requires the substitution of x = asin(t) with the bounds of the integral being 0 = asin(t) for the lower boundary and a = asin(t) for the upper boundary. After substituting, solve for t using the given limits and then plug in the results to evaluate the integral.
  • #1
vande060
186
0

Homework Statement



∫ x^2√(a^2 - x^2) dx evaluate integral from 0 to a







Homework Equations





The Attempt at a Solution



so i know the format of this problem requires the substitution of asinϑ -π/2 ≤ ϑ ≤ π/2 , but i don't know how to change the bounds of the integral after the substitution of ϑ. i just nedd help with this point the rest of the problem shouldn't be an issue
 
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  • #2
You're substituting x = a sin (t) so plug your limits into x then solve for t.
Ex:
0 = a sin(t) -> 0 = sin(t) -> arcsin(0) = t -> t = 0.

for upper boundary plug in x = a you get:

a = a sin(t) -> 1 = sin(t) -> arcsin(1) = t -> pi/2
 

FAQ: Question about where to start this trig substitution integral

What is a trig substitution?

A trig substitution is a technique used in calculus to solve integrals involving expressions containing trigonometric functions.

When should a trig substitution be used?

A trig substitution should be used when the integral contains a radical expression or an expression involving the square root of a sum or difference of squares.

How do you know which trig substitution to use?

The choice of trig substitution is determined by the form of the integral. For example, if the integral contains an expression of the form √(a^2-x^2), then the substitution x = a sinθ can be used.

Can any trig substitution be used for any integral?

No, the choice of trig substitution must be appropriate for the form of the integral. Using the wrong substitution can lead to incorrect solutions.

Are there any special cases where a trig substitution cannot be used?

Yes, trig substitutions cannot be used for integrals involving only polynomial or rational expressions. In these cases, other techniques such as u-substitution or integration by parts must be used.

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