Which functions are even? Check all the boxes that apply

for ex: the reciprocal of 3/4 is 4/3. it is the opposite.

reciprocal definition:

a mathematical expression or function so related to another that their product is one; the quantity obtained by dividing the number one by a given quantity.

1) letter c.

2) 4 square root of 9

hope this

step-by-step explanation:

11) obtuse

13)right

15) acute