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Reply 1
:rofl:
Reply 2
YYYY
:rofl:


Hey i need help on these questions and it probablly wont challenge you but help me anyway please :smile:.

Use the substituion u=5x+3 to find an exact value for ∫ 10x/ (5x+3)^3dx... btw it has limits of 3 and 0 i just couldnt put them in there.

The second is a vectors question:

Origion 0 and points A and B have position vectors i-5j-7k and 10i+10j+5k respectively. P is a point on line AB.

a)find a vector for the line passing through A and B
b) Find the position vector of point P such that OP is perpendicular to AB
c) Dind the area of triangle OAB.

:smile:
Reply 3
jakezg
Hey i need help on these questions and it probablly wont challenge you but help me anyway please :smile:.

Use the substituion u=5x+3 to find an exact value for ∫ 10x/ (5x+3)^3dx... btw it has limits of 3 and 0 i just couldnt put them in there.

The second is a vectors question:

Origion 0 and points A and B have position vectors i-5j-7k and 10i+10j+5k respectively. P is a point on line AB.

a)find a vector for the line passing through A and B
b) Find the position vector of point P such that OP is perpendicular to AB
c) Dind the area of triangle OAB.

:smile:

10x(5x+3)3dx\int \frac{10x}{(5x+3)^3} dx
u = 5x+3
dudx=5\frac{du}{dx} = 5
dxdu=15\frac{dx}{du} = \frac{1}{5}

the integral then becomes:

2u6(u)3.15du\int \frac{2u-6}{(u)^3}.\frac{1}{5} du
25u3u3du\frac{2}{5}\int \frac{u-3}{u^3} du
25u23u3du\frac{2}{5}\int u^{-2} - 3u^{-3} du

integrate that between 3 and 18.
Reply 4
he done it for me. Any more questions just post or mail me.

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