Math Is Fun Forum

  Discussion about math, puzzles, games and fun.   Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ • π ƒ -¹ ² ³ °

You are not logged in.

#1 2006-06-17 10:31:48

luca-deltodesco
Member
Registered: 2006-05-05
Posts: 1,470

integrating sqrt(1-x^2)

how would you go about integrating sqrt(1-x^2), ive only covered basic integration of functions like x^0.4 - 2x^3 for the moment, som i wouldnt know where to start with this


The Beginning Of All Things To End.
The End Of All Things To Come.

Offline

#2 2006-06-19 00:37:18

roah
Guest

Re: integrating sqrt(1-x^2)

if the integral is from (-1) to (1) you can use geometric interpretation. y^2+x^2=1 => y=sqrt(1-x^2) => a circle (a half of)
pi/2

#3 2006-07-22 21:29:32

krassi_holmz
Real Member
Registered: 2005-12-02
Posts: 1,905

Re: integrating sqrt(1-x^2)

Last edited by krassi_holmz (2006-07-22 21:31:07)


IPBLE:  Increasing Performance By Lowering Expectations.

Offline

#4 2006-07-23 10:09:26

mikau
Member
Registered: 2005-08-22
Posts: 1,504

Re: integrating sqrt(1-x^2)

this requires a trigonometric substitution. Or perhaps familarity with the derivitives of inverse trig functions. Did you come across this problem in your book/course? Or are you just curious?

Krasi, the thing that always bothers me with trig sub integration... I assume you let x = sin θ, but replacing cos θ with sqrt ( 1 - sin^2) is not necessarily a valid substitution. How can we get away with that?

Last edited by mikau (2006-07-23 10:14:30)


A logarithm is just a misspelled algorithm.

Offline

#5 2006-07-23 18:46:34

George,Y
Member
Registered: 2006-03-12
Posts: 1,379

Re: integrating sqrt(1-x^2)

You asked a very complexed question, luca. It involves virtuely every technique in integration.

#3 +C


X'(y-Xβ)=0

Offline

#6 2006-07-23 19:58:33

luca-deltodesco
Member
Registered: 2006-05-05
Posts: 1,470

Re: integrating sqrt(1-x^2)

i was actually hoping the answer wouldnt involve any trigometric functions, i looked up more integeration methods like inverse chain rule method and stuff, but they either didnt work for this, or gave one with trigometric functions


The Beginning Of All Things To End.
The End Of All Things To Come.

Offline

#7 2006-07-23 20:30:15

krassi_holmz
Real Member
Registered: 2005-12-02
Posts: 1,905

Re: integrating sqrt(1-x^2)

The arcsin() function is commonly used for integration.


IPBLE:  Increasing Performance By Lowering Expectations.

Offline

Board footer

Powered by FluxBB