# Quick integration question

by vorcil
Tags: integration
 P: 394 I need to figure out, $$\int_0^h \frac{1}{2\sqrt{hx}}dx$$ If h is a constant, how do i do this? my book shows that I can pull out, $$\frac{1}{2\sqrt{h}} \int \frac{1}{\sqrt{x}}dx$$ How does the 2 from $$\frac{1}{2\sqrt{hx}}$$ come out with the $$\sqrt{h}$$? I thought I would've only been able to pull out 1/root h, like this, $$\frac{1}{\sqrt{h}} \int \frac{1}{2\sqrt{x}}dx$$ - why does 2 root h get assigned constant? instead of only h
 HW Helper P: 6,202 1/2 is a constant, 1/√h is a constant it must follow that 1/2√h is constant as well.
Mentor
P: 21,258
 Quote by vorcil I need to figure out, $$\int_0^h \frac{1}{2\sqrt{hx}}dx$$ If h is a constant, how do i do this? my book shows that I can pull out, $$\frac{1}{2\sqrt{h}} \int \frac{1}{\sqrt{x}}dx$$ How does the 2 from $$\frac{1}{2\sqrt{hx}}$$ come out with the $$\sqrt{h}$$? I thought I would've only been able to pull out 1/root h, like this, $$\frac{1}{\sqrt{h}} \int \frac{1}{2\sqrt{x}}dx$$ - why does 2 root h get assigned constant? instead of only h
The basic idea is that $\int k*f(x) dx = k*\int f(x) dx$.

The rest in your problem is just algebra.
$$\frac{1}{2\sqrt{hx}} = \frac{1}{2*\sqrt{h}\sqrt{x}} = \frac{1}{2\sqrt{h}} \frac{1}{\sqrt{x}}$$

Integration is being done with respect to x (i.e., with x as the variable), so h is just another constant in this process.

 P: 394 Quick integration question cheers

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