Math Is Fun Forum

xXxEmZyxXx

Member

Registered: 2007-10-15

Posts: 12

integration

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

b300y

Member

Registered: 2007-10-17

Posts: 1

Re: integration

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

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))

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

George,Y

Member

Registered: 2006-03-12

Posts: 1,379

Re: integration

UHHHHHHHH...OHHHHHHHHHHHH

You are using complex integration, bossk!!!

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X'(y-Xβ)=0

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.

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

Identity

Member

Registered: 2007-04-18

Posts: 934

Re: integration

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

JaneFairfax

Member

Registered: 2007-02-23

Posts: 6,868

Re: integration

You could also just say that since

therefore

No need to mess around.

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.

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