Precalc 5.1 Trig Identities
Reciprocal Identities
csc x = 1/sinx
sec x = 1/cosx tan x = 1/cot x
sin x = 1/csc x
cos x = 1/sec x
cot x = 1/tan x
Quotient Identities
tan x = sinx/cosx
Cofunction Identities
cot x = cosx/sinx
PYTHAGOREAN IDENTITIES
sin2x + cos2x = 1
Even/Odd Identities
sin(-u) = -sin u
csc(-u) = -sin u
1 + cot2x = csc2x
1 + tan2x = sec2x
tan(-u) =-tan u
cot(-u) =-tan u
cos(-u) = cos u
sec(-u) = cos u
Dec 1­7:26 AM
Dec 1­7:49 AM
Simplify.
sinx
tanx
csc xtan x
cot xsin xtan x cot2x + sin2x + cos2x
sin x +cos2x
csc x
sec x ­ tan x
2
2
Dec 1­7:55 AM
Dec 1­7:58 AM
Verify trig identities. (Show left side of equation equals answer on right side of equation.) So, simplify one of sides to get answer on other side.
sin x = cos x
tan x
2
2
2
Dec 1­8:02 AM
Sep 10­10:42 AM
1