posted by Marie on .
could someone please tell me what the other angle identity of tan is? Thank you much!
"...other angle identity of tan x"?
in relation to which "other" ?
there are many identities dealing with the tangent.
The most important is probably
tan x = sin x/cos x
The Pythagorean Relationship would be
tan^2 x + 1 = sec^2 x
how about tan(2A) = 2tan A/(1-tan^2 A)
yes, i do know those, thank you. but my teacher told us that there is a specific identity for "the other angle". for example, the other angle identity of sinx = cos90-x. I believe the "other angle" identity for tanx is cot90-x but i'm not sure.
yes, you are right, tanx = cot(90-x)
if you are ever unsure about an identity like that pick an obscure angle such as 78.4º and test it with your calculator
tan 78.4 = 4.87162
cot(90-78.4)=cot 11.6º = 1/tan 11.6 = 4.87162