equation of the locus of the midpoint of the focal chord of the parabola y^2=64x
Answers
Answer:
y² = 32(x-16).
Step-by-step explanation:
Focus, S of the given parabola is (16,0).
Equaton of focal chord, that is a chord of a parabola which is passing through its fous is
y = m(x-16)-------(*), if we assume 'm' to be its slope.
For, equation(*) to be the chord of a parabola it has to intersect the parabola in 2 distinct points, let those be A (x₁, y₁) and B(x₂, y₂).
Solving y²=64x and y = m(x-16) we get
m²(x-16)²=64x,
m²x² -32x(m²+2) + 256m² = 0, whose roots are x1, x2.
So, Abcissa of the midpoint, X = (x₁ +x₂)/2 = 16(m²+2)/m²-----(1)
Ordinate of the midpoint, Y = m(x₁-16 +x₂-16)/2,
Y=m(X - 16)-----(2),
On eliminating m from eq(1) and (2), we get
y² = 32(x-16), which is the required locus of the midpoint of the focal chord of the given parabola.