Pythagorean Identity Flashcards
1
Q
What are the three pythagorean identities
A
Sin^2 +cos^2=1
Tan^2 +1=sec^2
Cot^2 +1 = csc^2
2
Q
Sin2x
A
2sinxcosx
3
Q
Cos2x
A
Sin^2x-cos^2x
2sin^2x-1
1-2cos^2x
4
Q
CosAcosB=
A
0.5(cos(A-B)+cos(A+B))
5
Q
SinAsinB=
A
0.5(cos(A-B)-cos(A+B))
6
Q
SinAcosB
A
0.5(sin(A+B)+sin(A-B))
7
Q
Cosx +cosy=
A
=2cos((0.5)x+y)cos((0.5)x-y)
8
Q
Cosx-cosy
A
=-2cos((0.5)x+y)cos((0.5)x-y)
9
Q
Sinx + siny
A
2sin((0.5)x+y)cos((0.5)x-y)
