4) ΔPNE подобен Δ MPK ( коэффициент подобия = 5/8)
NE = 5/8*12 = 5/2 * 3 = 15/2 = 7,5
→ → → →
5) Сosα = MN*KP/|MN|*|KP|
→ → → →
MN{-3;-3;2}, KP{2;0;0}, ⇒ MN*KP = -6 +0 +0 = -6
→ →
|MN| = √(9 +9 +4) =√22, |KP| = √(4 + 0 + 0) = √4 = 2,
Cosα = -6/2√22 = -3/√22 = -3√22/22