# Math Help - Positive Value of x

1. ## Positive Value of x

What is a positive value of x for which 9^(-cos x) = 1/3?

NOTE: The (-cos x) is the exponent in this case.

2. Originally Posted by magentarita
What is a positive value of x for which 9^(-cos x) = 1/3?

NOTE: The (-cos x) is the exponent in this case.
I'll nudge you in the right direction:

$9^{-\cos(x)}=\frac{1}{3}$

Note that $\frac{1}{3}=3^{-1}$ and $9=3^2$

So we can rewrite the equation as this: $3^{-2\cos(x)}=3^{-1}$

I'm sure you can take it from here.

--Chris

3. ## yes.....

Originally Posted by Chris L T521
I'll nudge you in the right direction:

$9^{-\cos(x)}=\frac{1}{3}$

Note that $\frac{1}{3}=3^{-1}$ and $9=3^2$

So we can rewrite the equation as this: $3^{-2\cos(x)}=3^{-1}$

I'm sure you can take it from here.

--Chris
Yes, I can. Thank you.