#Find value of integral
1 messages · Page 1 of 1 (latest)
Hint: let $u=\sqrt{x}$
Amer
Well yeah I know how to solve it but it takes like 20 mins to solve it
In the exam i have 5 mins
I used this
Ok let me try it $\int 2u\sqrt{u^2+u} ; du$
Amer
Ok another $\int \sqrt{x}\sqrt{1+\frac1{\sqrt{x}}}$
Amer
Set $u=1+1/\sqrt{x}$ then $dx=-2x^{3/2}$
Amer
Ok and
The first sub $(u+\frac12)\sqrt{(u+\frac12)^2-\frac14}-\frac12\sqrt{(u+\frac12)^2-\frac14}du$
The first integral the outside is the derivative of the inside
Amer
The second integral we use $\sec w=2(u+\frac12)$ so the sqrt will be just tan w
Amer