Question

Panjang vektor XY = 12, jika X(2,a) dan Y(0,-2) maka nilai a adalah...

Answer 1

|XY| =√(2 - 0)² + (a - (-2))²
12 = √(4 + a² + 4a + 4)
144 = a² + 4a + 8
a² + 4a - 136 = 0
a₁,₂ = (- 4 +- √(16 - 4(1)(-136))/2
      = (-4 +- √(560))/2