Question

**PRE-CALC HELP PLEASE How to verify the identity tan(x+pi/2)=-cotx ?

Answer 1

Do I USE the cofunction identity?

Answer 2

You use whatever works. Let's see what happens when you use the cofunction identity.

Answer 3

tan(x+y) = (tan x +tan y) / (1- tan x tan y)

Answer 4

here y is pi/2

Answer 5

ooooh I see so x is x and y is pi/2?

Answer 6

yes

Answer 7

so x + pi/2/ 1-x + pi/2 ?

Answer 8

is that correct?

Answer 9

no

Answer 10

tan x + tan 90/ (1- tan90 *tanx)

Answer 11

then divide numerator and denominator by tan 90 .
as u know tan 90 is "infinite"
and 1 / "infinte" = 0

Now try to solve it

Answer 12

no

Answer 13

(tan x/tan 90+1 ) / [(1 /tan 90) - tanx)]

Answer 14

got it ?