Hello

1 Derivate the function $\displaystyle \frac{3}{\sqrt{x - 9} }$

2 General solution for $\displaystyle y' - 3y = e^{-2x} + 2$

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1 I think I have solved this:

First, lets see the expression as two factors:

$\displaystyle 3 * (x - 9)^{-\frac{1}{2}}$

Derivate of an product $\displaystyle u' * v + u * v'$

Gives us:

$\displaystyle 3* -\frac{1}{2}(x - 9)^{-\frac{3}{2}} + 0 * (x - 9)^{-\frac{1}{2}}$

$\displaystyle \frac{3}{2(x - 9)^{\frac{3}{2}}}$

2, I don't know, we haven't really studied differential equations that much.

Thanks for all replies