Question

How do you find the value of `cot (pi/2)`?

Answer 1

You can use two trig identities: `cotx = 1/tanx` and `tanx = (sinx)/(cosx)`.

`cotx = 1/tanx = cosx/sinx`

`pi/2 "rad" = 90^o`

`sin 90^o = 1`
`cos 90^o = -1`

`cot90^o = (cos90^o)/(sin90^o) = (-1)/(1) = -1`