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#1 2007-10-22 06:11:18

xXxEmZyxXx
Member
Registered: 2007-10-15
Posts: 12

integration

intergrate tanh(2x+1)dx
please help!!!

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#2 2007-10-22 06:13:26

b300y
Member
Registered: 2007-10-17
Posts: 1

Re: integration

x=1  and i dont know were the d comes from

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#3 2007-10-22 09:38:10

bossk171
Member
Registered: 2007-07-16
Posts: 305

Re: integration

∫ tanh(2x+1) dx = (1/2)ln(cosh(2x+1))

tanh(u) = -i*tan(iu)     ( i = √(-1) )

u = 2x+1
du = 2 dx
thus:
(1/2) du = dx

∫ -i*tan(iu) (1/2)du = (-i/2)∫tan(iu) du = (1/2)(ln(|cos(iu)|) + C

cosh(u) = cos(iu)

(1/2) ln(cosh u) + C = (1/2)ln(cosh(2x+1))


There are 10 types of people in the world, those who understand binary, those who don't, and those who can use induction.

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#4 2007-10-27 13:49:15

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

Re: integration

UHHHHHHHH...OHHHHHHHHHHHH

You are using complex integration, bossk!!!


X'(y-Xβ)=0

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#5 2007-10-27 18:14:50

bossk171
Member
Registered: 2007-07-16
Posts: 305

Re: integration

Did I do something wrong? I was kind of just winging it, and my answer matched The Integrator's.


There are 10 types of people in the world, those who understand binary, those who don't, and those who can use induction.

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#6 2007-10-27 19:48:41

Identity
Member
Registered: 2007-04-18
Posts: 934

Re: integration

It's so much fun messing around with the integrator!

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#7 2007-10-27 22:24:15

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

Re: integration

You could also just say that since

therefore

No need to mess around. shame

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#8 2007-10-28 23:15:13

bossk171
Member
Registered: 2007-07-16
Posts: 305

Re: integration

I always use the integrator when I'm helping someone out, because with integration I tend to make stupid little mistakes, so I always make sure I'm right... so I don't mislead the person asking the question.


There are 10 types of people in the world, those who understand binary, those who don't, and those who can use induction.

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