The point (8,-15) lies in quadrant 4.
In quadrant 4, we draw a right triangle with legs 8 and -15 and hypotenuse 17. See picture.
I will use t for theta. My phone does not have the theta key.
sin t = -15/17
cos t = 8/17
tan t = -15/8
csc t = -17/15
sec t = 17/8
cot t = 8/-15
In quadrant 4, all trig functions are negative except for cosine and its reciprocal function secant.
