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## #1 Re: Help Me ! » Integration Problem » 2006-01-05 02:13:39

Cheers the quick response.

Where did the numbers come from though?

Is the two there because (2t)² = 4t², and thus 2t was actually the correct "t" to go there... and is it all divided by two because it was actually two variables being used instead of the intended one?

## #2 Help Me ! » Integration Problem » 2006-01-05 01:42:05

Andorin
Replies: 4

Howdy folks,

I'm just running through my maths book and have got stuck on solving this problem. Being... find the value of:

∫[1,0] 1/√(9-4t²) dt

Try as I might I just cannot work out the correct way to integrate this. I've been trying to use this conversion method:

f'(x) = 1/√(a²-t²)   ≈   f(x) = sin-¹(t/a)+c

But I don't get the right answer according to the book no matter what I do. The book says that the value should be 0.365, but I just don't seem to hit the jackpot no matter how I arrange it. I'm assuming it has something to do with the co-efficient of 4 but hey, who knows. Hopefully one of you do and can explain where I'm going wrong..

## #3 Help Me ! » Finding a Cubic Equation from Complex Roots » 2005-10-30 09:07:02

Andorin
Replies: 1

Hi,

An exercise is my workbook asks to find a cubic equation with roots of 2, 1+j and 4+2j (where j is the the square root of -1). I am lost as to how to work this out. Any chance of someone guiding me through?

## #4 Help Me ! » Partial Fractions with Repeated Factors » 2005-10-24 03:05:27

Andorin
Replies: 2

Hi,

I'm trying to solve a particular partial fraction namely:

2X^2 - X + 1
-------------------
(X + 1)(X - 1)^2

I am aware of the fractions that it is meant to split into... the numerators are all meant to be 1.

Its how on earth they get there that confuses me.

I can work C out (in terms of there being three constants/numerators named A, B and C) as being 1 but then I get A as being 1/2... what am I doing wrong??? Or is the book I'm working from barkers?

Could someone run me through this one?