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Alpha:

--- Quote from: Zara on May 22, 2010, 03:49:54 pm ---Q2) Find the integral of

root of (4-x^2) ; use substitution x=2sintheta

im stuck half way :\  hellpp please =)

--- End quote ---

I'll use @ for theta.

x = 2 sin 2
x^2 = 4 sin^2 @

/ for root.

/ (4 - x^2) = / [4(1-sin^2@)]

Using identity sin^2@ + cos^2@ = 1,

/ [4(1-sin^2@)] = / 4 cos^2@
                        = 2 cos @

Now integrate.

Differentiation of sin@ > cos@,

Integration of cos@ > sin@.

Integrate 2 cos@ > 2 sin@.

Twinkle Charms:
oh ohkay i got it, was skippin one step, Thank You..

Twinkle Charms:
Q3)Integral of (50-m)^-2??

 the answer given is (50-m)^-1 buh im gettin -(50-m)^-1, where am i rong?:S

astarmathsandphysics:
You are ignoring the - in -m

Twinkle Charms:

--- Quote from: astarmathsandphysics on May 23, 2010, 11:27:19 am ---You are ignoring the - in -m

--- End quote ---
ohh so we mutiply -1 in the denominator with -1 to get +1? ohkk...Thank You astar=)

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