# Math Help - Multipling radicands

sqrt{-25}*sqrt{-4}

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

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

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

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

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

=-10

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

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

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