Question

tolong bantu jawab kak​

Answer 1

• No. 9 ➛ = 135°
• No. 10 ➛

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Answer 2

Penjelasan dengan langkah-langkah:

V E K T O R

9. A(1, –2, –1)

B(4, 1, –1)

C(2, 0, 1)

u = AB = (3, 3, 0)

v = BC = (–2, –1, 2)

u.v = –6–3+0

u.v = –9

|u| = √(3²+3²) = 3√2

|v| = √[(–2)²+(–1)²+2²) = √9 = 3

cos a = u.v

|u||v|

cos a = –9

3.3√2

cos a = –9

9√2

cos a = –½√2 ✔

a = 135° atau 225°

10. A(1, –2, –1)

B(5, 0, –1)

C(2, 0, 1)

u = BC = (–3, 0, 2)

v = AC = (1, 2, 2)

u.v = 1.(–3)+2.0+2.2

u.v = –3+0+4 = 1

|v|² = [√(1²+2²+2²)]²

|v|² = [√(1+4+4)]²

|v|² = [√9]²

|v|² = 9

w = u → v

w = u.v (AC)

|v|²

w = 1 ( 1, 2, 2)

9

w = (1/9, 2/9, 2/9)

w = i + 2j + 2k ✔

9 9 9