Hello!
The answer is:

Why?
Since it's a right triangle, and we have the adjacent and opposite sides size (
), we can solve it using following the next steps:
Tan(u),
We can find the tangent using the following formula:

Sin(u),
To find the sin(u) we need first to find the hypotenuse of the triangle using the Pythagorean Theorem, so:

Where:

Substituting we have:


Then, we can calculate the sin(u) using the following formula:

Finally, we can calculate the cos(u) by using the following formula:
Cos(u),

Hence,
We have that:

Have a nice day!