trig identities Flashcards
cscx =
1/ sinx
secx =
1/ cosx
cotx =
1/ tanx
tanx =
sinx/ cosx
cotx =
cosx/ sinx
1 =
cos²x + sin²x
sec²x =
1 + tan²x
csc²x =
1 + cot²x
sin(-x) =
-sinx
cos(-x) =
cosx
tan(-x) =
-tanx
cos²x =
1 - sin²x
sin²x =
1 - cos²x
-sin²x =
cos²x - 1 → -1 + cos²x
sin(A + B)=
sinAcosB + cosAsinB
cos(A + B)=
cosAcosB - sinAsinB
tan(A + B)=
1 - tanAtanB
sin(A - B)=
sinAcosB - cosAsinB
cos(A - B)=
cosAcosB + sinAsinB
tan(A - B)=
1 + tanAtanB
sin2θ=
2sinθcosθ
cos2θ=
Both cos and sin
cos^2θ - sin^2θ
cos2θ=
Just cos
2cos^2θ - 1
cos2θ=
Just sin
1 - 2sin^2θ
tan2θ=
1 - tan^2θ
sin(θ/2)=
+- root 1-cosθ/ 2
cos(θ/2)=
+- root 1 + cosθ/ 2
tan(θ/2)=
+- root 1 - cosθ/1 + cosθ
(Reducing powers)
sin^2x=
2
(Reducing powers)
cos^2x
2
(Reducing powers)
tan^2x=
1 + cos2x
(Co function identities)
cosx=
sin(pi/2 - x)
sin(90• - x)
(Co function identities)
cotx=
tan(pi/2 - x)
tan(90• - x)
(Co function identities)
cscx=
sec(pi/2 - x)
sec(90• - x)
(Co function identities)
sinx=
cos(pi/2 - x)
cos(90• - x)
(Co function identities)
tanx=
cot(pi/2 - x)
cot(90• - x)
(Co function identities)
secx=
csc(pi/2 - x)
csc(90• - x)
(Product sum identities)
sinxcosy=
1/2[sin(x+y) + sin(x+y)]
(Product sum identities)
cosxsiny=
1/2[sin(x+y) - sin(x-y)]
(Product sum identities)
sinxsiny=
1/2[cos(x-y) - cos(x+y)]
(Product sum identities)
cosxcosy=
1/2[cos(x+y) + cos(x-y)]
(Sum-product identities)
sinx + siny=
2sin(x+y / 2)•cos(x-y / 2)
(Sum-product identities)
sinx - siny=
2cos(x+y / 2) • sin(x-y / 2)
(Sum-product identities)
cosx + cosy=
2cos(x+y / 2) • cos(x-y / 2)
(Sum-product identities)
cosx - cosy=
-2sin(x+y / 2) • sin(x-y / 2)
Amplitude=
2
Vertical shift (d)+
2
B=
P
X’=
xcostheta - ysintheta
Y’=
xsintheta + ycostheta