Trig Flashcards
sin2x=
2sinxcosx
cos2x=
= (cosx)^2 - (sinx)^2
= 2*(cosx)^2 - 1
sina + sinb =
2* sin[(a+b)/2] * cos[(a-b)/2]
sina-sinb=
2* sin[(a-b)/2] * cos[(a+b)/2]
cosa+cosb=
2cos[(a+b)/2]cos[(a-b)/2]
cosa-cosb=
-2sin[(a+b)/2]sin[(a-b)/2]
sina*cosb=
1/2*[sin(a+b)+sin(a-b)]
cosa*cosb=
1/2*[cos(a+b)+cos(a-b)]
sina*sinb=
-1/2*[cos(a+b)-cos(a-b)]
f: {a1, a2, …, an} -> {b1, b2, …, bm}
Nr fct inj= ?
Aranjamente de n luate cate m
f: {a1, a2, …, an} -> {b1, b2, …, bm}
Nr fct surj= ?
Combinari de n luate cate m
f: {a1, a2, …, an} -> {b1, b2, …, bm}
Nr total de fct=?
N^m
z= a + ib
|z| =
Sqrt( a^2 + b^2 )
z= a + ib
|z|^2 =
z * z conj
p=
(a+b+c)/2
S=
=(bcsinA)/2
= a*ha / 2
= sqrt( p(p-a)(p-b)(p-c) )
= abc/4R
2R=
a/sinA = b/sinB = c/sinC
cosA =
b^2 + c^2 - a^2 / 2bc
r =
S/p
Integr tg x dx =
- ln |cosx|
Integr ctgx dx =
ln |sinx|
Integr 1/cos^2 x dx =
tg x
Integr 1/sin^2 x dx =
ctg x
Integr 1/(x^2 - a^2) dx =
1/2a * ln | x-a / x+a |
