# Thread: Multipling radicands

1. ## Multipling radicands

sqrt{-25}*sqrt{-4}

2. ## Re: Multipling radicands

Originally Posted by purplec16
sqrt{-25}*sqrt{-4}
Note that the familiar property, $\displaystyle \sqrt a\sqrt b = \sqrt{ab}$ applies only to nonnegative $\displaystyle a$ and $\displaystyle b$. Instead, we have

$\displaystyle \sqrt{-25}\sqrt{-4}$

$\displaystyle =\left(i\sqrt{25}\right)\left(i\sqrt4\right)$

$\displaystyle =(5i)(2i) = 10i^2$.

Now, what is $\displaystyle i^2$? Simplify.

=-10

4. ## Re: Multipling radicands

What do you wrap the latex in? I am for some reason unable to do it/ find it?

5. ## Re: Multipling radicands

Originally Posted by purplec16
What do you wrap the latex in? I am for some reason unable to do it/ find it?
Enclose your LaTeX in $$and$$ tags. For example,

$$\sum_{n=1}^{\infty}\frac{1}{n^2}=\frac{\pi^2}6$$

yields

$\displaystyle \sum_{n=1}^{\infty}\frac{1}{n^2}=\frac{\pi^2}6$

Your answer is correct, by the way.

Thank you!!!