Let (-7, -4) be a point on the terminal side of theta. find the exact values of sin, csc and cot

First you need to get the radius of the circle. We do that by using the (x,y) point. So we have (-7, -4).

To get the radius, we us the following formula. 

r = √(-7)² + (-4)²

This reads: 
radius = square root of -7 to the power of 2 plus -4 to the power of 2.

I am new here and I am not sure if they support latex. Other wise I would of used latex. 

Ok so r (radius) =  r = √(-7)² + (-4)² =  √65

r = √65

Now we have our radius we can find the values for sin csc and cot

sin  =  y / r
csc = r / y 
cot =  x / y

I will do the first one for you which is sin. 

sin = y / r  =  -4 / √65

The above is saying sin = y divided by r =  -4 divided by the square root of 65.

If you need help with the others let me know. 

The above is saying sin = y divided by r = -4 divided by the square root of 65.