Question

Tolong di jawab pake cara
mksii

Answer 1

BA = A - B
= (4, 2, 3) - (1, 0, -1)
= (3, 2, 4)

BC = C - B
= (3, 3, -4) - (1, 0, -1)
= (2, 3, -3)

BA.BC = ||BA|| ||BC|| cos t
3.2 + 2.3 + 4.-3 = √(3² + 2² + 4²) . √(2² + 3² + (-3)²) . cos t
6 + 6 - 12 = √(3² + 2² + 4²) . √(2² + 3² + (-3)²) . cos t
0 = √(3² + 2² + 4²) . √(2² + 3² + (-3)²) . cos t
cos t = 0

arc cos 0 = t
t = 90°
t = π/2