1. ## Cuboid

We’ve got cuboid ABCDA’B’C’D’.
$\displaystyle \alpha$ = $\displaystyle \angle$ C’AB
$\displaystyle \beta$ = $\displaystyle \angle$ C’AD
$\displaystyle \gamma$ = $\displaystyle \angle$ C’AA’
Prove that:
tg $\displaystyle \alpha$ + tg $\displaystyle \beta$ +tg $\displaystyle \gamma$ ≤ $\displaystyle \frac {3}{2}$ tg $\displaystyle \alpha$ tg $\displaystyle \beta$ tg $\displaystyle \gamma$

2. ## Re: Cuboid

What does tg refer to?

3. ## Re: Cuboid

It's tg angles $\displaystyle \alpha , \beta , \gamma$

4. ## Re: Cuboid

Originally Posted by chiro

What does tg refer to?
It's tg angles $\displaystyle \alpha , \beta , \gamma$
Okay. So what is a tg angle? Please give us the definition.

-Dan

5. ## Re: Cuboid

I expect it means \displaystyle \displaystyle \begin{align*} \tan{\alpha}, \tan{\beta}, \tan{\gamma} \end{align*}.

6. ## Re: Cuboid

Yes, this is tan.

7. ## Re: Cuboid

I tried to use Inequality of arithmetic and geometric means, but nothing's good. So, have you got any idea?