А) N(-1; 0; 5), B(3;-1;7)
|BN| = √(4² + 1² + 2²) = √21
б) → → → →
CA{-1;0;5}, CB{-3; 3;-3}, |CA| =√(1 +0 +26) =√27, |CB| =√(9 +9 +9)=√27
→ → → →
CosC = CA*CB/|CA|*|CB| = (3 +0 -15)/(√27*√27)= -12/27 = -4/9
-3
0
|П-4|
√4
√5
5,(4)
7
Пожалуйста)
6x²-12x+p=0|:6
x²-2x+p/6=0
По теореме Вието
x1+x2=-p=-(-2)=2
x1*x2=q=p/6
x2=5x1
x1+5x1=2
6x1=2
x1=2/6
x1=⅓
⅓*5*⅓=p/6
5:9=p:6
9p=5*6=30
p=30/9=3(3/9)
p=3⅓
9^x - 8·3^x· 3 +63 = 0
9^x - 24· 3^x + 63 = 0
3^x = t
t² - 24 t +63 = 0
t = 21 и t = 3
3^x = 21 3^x = 3
xlg3 = lg21 x = 1
x = lg21 /lg3