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#1 2007-03-21 11:50:56

dukebdx12
Member
Registered: 2007-03-21
Posts: 9

Calc 2 help

Calculus 2 help?
Need help with these questions. I have a test tomorrow and need help on knowing how to work these.....S stands for integration. And just help on any of these would be fine. Thanks
1) S 2/(x-9)^2 dx .... i got the answer -2/(x-9) but how did they get that because as far as I got is 2S1/(u^2) dx

2) S [x + 1/(3x-1)^3] dx

3) S (x^2-3)/(-x^3+9x+1) dx ......long division?

4) cotx ln(sinx) dx ........ havn't tried to work it yet.

5) S 2/((2x-1)^2+4) dx ...here you use arctan formula which is du/a^2+u^2 = 1/a arctan(u/a)+c and I have kinda got a and u figured out just need help putting in because this is diff. from what we did in class.

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#2 2007-03-21 13:44:12

JaneFairfax
Member
Registered: 2007-02-23
Posts: 6,868

Re: Calc 2 help

(1)

In general,

(2)Try putting the integrand into partial fractions.

(3)

(4)
Notice that

(5)
Try the substitution

Last edited by JaneFairfax (2007-03-21 14:03:10)

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#3 2007-03-21 14:01:28

Stanley_Marsh
Member
Registered: 2006-12-13
Posts: 345

Re: Calc 2 help

Can I use

in 2??

Numbers are the essence of the Universe

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#4 2007-03-21 14:05:41

JaneFairfax
Member
Registered: 2007-02-23
Posts: 6,868

Or just

. Thatll work.

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