Question 5: prove that it’s =0

Proof in explanation.

Step-by-step explanation:

I'm going to attempt this by squeeze theorem.

We know that is a variable number between -1 and 1 (inclusive).

This means that .

for all value . So if we multiply all sides of our inequality by this, it will not effect the direction of the inequalities.

By squeeze theorem, if  

and , then we can also conclude that .

So we can actually evaluate the "if" limits pretty easily since both are continuous  and exist at .

.

We can finally conclude that by squeeze theorem.

Some people call this sandwich theorem.

it would be 6xy and -16xy.