For the quadrant in which the following point is located, determine which of the functions are positive. (2, -4) sin cos tan sec csc cot

Hi i’m not sure how to do question 20 if u could explain how to do it that’d b great

Use mathematical induction to prove the statement is true for all positive integers n, or show why it is false. 1^2 + 4^2 + 7^2 + + (3n - 2)^2 = [n(6n^2-3n-1)/2]

Which situation is an example of an observational study?