Ad Infinitum!!

I have been sitting on this problem for an hr but it will be simple for u guys........ My brain hasn't been working too well after spending 5 days reading biology!!!

\int (3x-2)\sqrt{x^{2}+x+1}

6 Answers

21
tapanmast Vora ·

This is a typical question.

Ani : I = L√Q

wer L = linear; Q = quad

Express linear as t(∂Q/∂x).................... wer t = const. to adjust "3" of 3x

now ur I bcums

I = t * ∂Q/∂x * √Q + t' √Q .............. wer t' is the remain over of of ur original const. in L i.e. -2

NOW U CAN DO IT

1
Optimus Prime ·

let (3x-2) = A.(d/dx(x2+x+1)+ B

then 3x-2=2Ax+A+B

then 2Ax=3x

A=3/2

A+B=-2

B=-7/2

therefore

(3x-2)=3/2(2x+10)-7/2

∫(3x-2)√x2+x+1 dx = ∫3/2(2x+1) -7/2∫√X2+X+1 DX

=3/2∫(2X+1)√X2+X+1 DX - 7/2 ∫√X2+X+1 DX

I THINK U CAN SOLVE FURTHER BY TAKING X2+X+1=T

11
Anirudh Narayanan ·

\int \left[ \frac{3}{2}(2x+1)-\frac{7}{2} \right]\sqrt{x^{2}+x+1}\: dx

So we have to express it like this and then proceed???

PS:
BTW, in what way is ∂Q/∂x different from dQ/dx??

11
Anirudh Narayanan ·

Sorry amit....didn't see ur post...

That question was to tapan

21
tapanmast Vora ·

no diff

11
Anirudh Narayanan ·

So everyone writes ∂Q/∂x just to sound more funda-like?? [3]

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