Answer:

Explanation:
Remember that the tangent trigonometric ratio is the opposite side of right triangle divided by the adjacent side:


Comparing the equations we can infer that:
opposite side = 4
adjacent side = 3
Now we can use Pythagoras to find the hypotenuse of our right triangle:





Remember that the cosine trigonometric ratio is the adjacent side divided by the hypotenuse; in other words:

We know that adjacent side = 3 and hypotenuse = 5.
Replacing values:

Now, remember that cosine means x and sine means y. In Quadrant 2 x is negative, which means that cosine is negative.
So, if
in quadrant 2, then
