Can someone please help me I need to get this done by the end of the day, ill also give Brainliest to the first person.

Which graph represents an even function?

Evaluate cos2θ for cosθ = square root of 3/2

Is the product of two rational numbers irrational or rational? first, make a hypothesis by multiplying two rational numbers. then, use variables such as x=a/b and y=c/d and the closure property of integers to prove your hypothesis.