Question

Which function is undefined when x=pi/2 radians?
cos x
cot x
csc x
tan x

Answer 1

The first two are 0 and the last one is infinity... not sure which one is undefined

Answer 2

undefined is when you try to divide by 0. For example, 1/0 is undefined.

Answer 3

cos(pi/2)=0. That's defined. If you have a calculator and try to input the choices, the ones that give you an error message are undefined.

Answer 4

cot(x)=1/tan(x)=1/tan(pi/2)=undefined.