Question

The equation of the locus of a point whose distance from (a, 0) is equal to its distance from y-axis, is.

• A. $y^{2} - 2ax = a^{2}$
• B. $y^{2} - 2ax + a^{2} = 0$
• C. $y^{2} + 2ax + a^{2} = 0$
• D. $y^{2} + 2ax = a^{2}$

Answer 1

Answer: (B)

$y^{2} - 2ax + a^{2} = 0$

Answer 2

Let the point be $( h , k )$

So,$( h - a ) ^ { 2 } + ( k - 0 ) ^ { 2 } = h ^ { 2 }$ $\Rightarrow h ^ { 2 } + a ^ { 2 } - 2 a h + k ^ { 2 } = h ^ { 2 }$

Hence locus is $y ^ { 2 } - 2 a x + a ^ { 2 } = 0$.