Trig Flashcards
1
Q
sin2x=
A
2sinxcosx
2
Q
cos2x=
A
= (cosx)^2 - (sinx)^2
= 2*(cosx)^2 - 1
3
Q
sina + sinb =
A
2* sin[(a+b)/2] * cos[(a-b)/2]
4
Q
sina-sinb=
A
2* sin[(a-b)/2] * cos[(a+b)/2]
5
Q
cosa+cosb=
A
2cos[(a+b)/2]cos[(a-b)/2]
6
Q
cosa-cosb=
A
-2sin[(a+b)/2]sin[(a-b)/2]
7
Q
sina*cosb=
A
1/2*[sin(a+b)+sin(a-b)]
8
Q
cosa*cosb=
A
1/2*[cos(a+b)+cos(a-b)]
9
Q
sina*sinb=
A
-1/2*[cos(a+b)-cos(a-b)]
10
Q
f: {a1, a2, …, an} -> {b1, b2, …, bm}
Nr fct inj= ?
A
Aranjamente de n luate cate m
11
Q
f: {a1, a2, …, an} -> {b1, b2, …, bm}
Nr fct surj= ?
A
Combinari de n luate cate m
12
Q
f: {a1, a2, …, an} -> {b1, b2, …, bm}
Nr total de fct=?
A
N^m
13
Q
z= a + ib
|z| =
A
Sqrt( a^2 + b^2 )
14
Q
z= a + ib
|z|^2 =
A
z * z conj
15
Q
p=
A
(a+b+c)/2
