Wednesday

October 1, 2014

October 1, 2014

Posted by **O_o Rion** on Saturday, December 5, 2009 at 8:31pm.

In an integration solution, the integral of (1/(sqrt (8-u squared)) is written as arcsin(u/sqrt 8), but I dont see how they got it. When I did it I got (1/8)*(arcsin(u*sqrt8)). What I did was take sqrt8 common in the denominator to get it in the form sqrt(1-u sq.) and then find the integral (arcsin u) and then since my 'u' was sqrt.8 * u, I divided sqrt.8 from the whole thing. Where did I go wrong?

- Calculus -
**MathMate**, Sunday, December 6, 2009 at 9:20am"take sqrt8 common in the denominator to get it in the form sqrt(1-u sq.)"

Shouldn't it be

1/sqrt(8-u^2)

=(1/sqrt(8))/(1-(u**/sqrt(8)**)^2)

When you do a substitution, it is always advisable to use a different letter. You are likely to confuse yourself if you use the same letter, namely, substitute u by u/sqrt(8).

Try:

w=u/sqrt(8)

then

dw=du/sqrt(8)

and

∫ du/sqrt(8-u^2)

=∫ du/(sqrt(8))/(1-(u/sqrt(8)))

=∫ dw/(1-w^2)

=asin(w)

=asin(u/sqrt(8))

- Calculus -
**Laurie**, Thursday, May 24, 2012 at 12:44pmsquare root of (1-u squared)

**Answer this Question**

**Related Questions**

calculus - How do you find: the Integral of arcsin(1 / (sqrt x^2 - 1) ) dx ?? (...

calculus-integration! - should i use substitution?? if yes how should should i ...

Calculus - Evaluate the indefinite integral: 8x-x^2. I got this but I the ...

Math/Calculus - Solve the initial-value problem. Am I using the wrong value for ...

Calculus - Find the volume of the solid whose base is the region in the xy-plane...

Calculus - Hello Everyone, I need help with Calc II. 1. Integral from 0 to 1 of...

calculus II - Using integration by substitution. find the exact value of ...

Calculus AP - hi again im really need help TextBook: James Stewart:Essential ...

Calculus URGENT test tonight - Integral of: __1__ (sqrt(x)+1)^2 dx The answer is...

CALCULUS 2!!! PLEASE HELP!! - I'm having trouble with this question on arc ...