# Integral help

1. Mar 9, 2008

If you are told to evaluate the integral and are given this problem:

∫ (e√x / √x) dx

This reads that the integral of (e) to the power of square root of x divided by the square root of x multiplied by the derivative of x is……

I have tried solving it and came up with this, is this correct if not please show me what I did wrong and how I can solve it.

y = x2 + 2

y = sin x

0 ≤ x ≤ π
π π π π
A(D) = ∫0 (x2 + 2 – sin x) dx = ∫0 x2dx + 2 ∫0 dx - ∫0 sin x dx =

π π π
[x 3 / 3 ]0 + 2[x]0 + [cos x]0 = π/3 + 2π – 2

π
[cos x]0 = cos π – cos 0 = -1 – 1 = -2

Is this correct?

the integral goes from zero to pi. and x2 is x squared. Any help is appreciated.

2. Mar 9, 2008

### rock.freak667

$$\int \frac{e^{\sqrt{x}}}{\sqrt{x}} dx$$

Let $t=\sqrt{x} \Rightarrow \frac{dt}{dx}=\frac{1}{2\sqrt{x}} \Rightarrow 2 dt=\frac{dx}{\sqrt{x}}$

Can you take it from here?

Last edited: Mar 9, 2008
3. Mar 12, 2008

now do you turn the square root of x into the power of 1/2, then you raise it to the numerator it becomes -1/2, the direvative of that is 1/2 divided by one whic is one half. correct?

4. Mar 12, 2008

### rocomath

No ... if you u-sub the sqrt of x in the numerator and take the derivative, a part of your integral will appear which lets you get rid of the one in the denominator.

5. Mar 12, 2008

### rocomath

$$\int e^{\sqrt{x}}\frac{dx}{\sqrt x}$$

$$u=\sqrt x$$
$$du=\frac{dx}{2\sqrt x} \rightarrow 2du=\frac{dx}{\sqrt x}$$

Now make your substitutions ... hope this is a little more clear.

$$2\int e^u du$$

Last edited: Mar 12, 2008