Geometrie Flashcards
1
Q
Teorema cosinusului in ΔABC
A
BC^2 = AB^2 + AC^2 - 2⋅ AB⋅ AC ⋅ cos A
2
Q
Teorema sinusurilor
A
a/sin A = b/sin B = c/sin C = 2R
3
Q
Panta unei drepte
A
m = y2 - y1 / x2 - x1
4
Q
Ecuatia dreptei cu panta m care trece prin punctul A
A
y - y’ = m(x - x’)
5
Q
Ecuatia dreptei care trece prin 2 puncte date
A
x - x1/ x2 - x1 = y - y1 / y2 - y1
6
Q
Conditia de perpendicularitate a 2 drepte
A
m1 ⋅ m2 = -1
7
Q
Conditia de paralelism a 2 drepte
A
m1 = m2
8
Q
Perpendicularitate pt:
v = ai + bj
w = a2i + b2j
A
a1 ⋅ a2 + b1 ⋅ b2 = 0
9
Q
Coliniaritate a 2 vectori
A
a1/a2 = b1/b2
10
Q
Coliniaritate a 3 puncte in plan
A
det [ xn yn 1] = 0
11
Q
A, B puncte in plan => vector AB =
A
(x2 - x1)i + (y2 - y1)j
12
Q
Distanta dintre punctele A, B
A
√[ (x2 - x1)^2 + (y2 - y1)^2 ]
