Question
Question: If the point (*x, y*) be equidistant from the points \((a + b,b - a)\) and \((a - b,a + b)\), then...
If the point (x, y) be equidistant from the points (a+b,b−a) and (a−b,a+b), then
A
ax+by=0
B
ax−by=0
C
bx+ay=0
D
bx−ay=0
Answer
bx−ay=0
Explanation
Solution
Let points P(x,y), A(a+b,b−a), B(a−b,a+b).
According to Question, PA=PB, i.e., PA2=PB2
⇒(a+b−x)2+(b−a−y)2=(a−b−x)2+(a+b−y)2⇒(a+b)2+x2−2x(a+b)+(b−a)2+y2−2y(b−a)
=(a−b)2+x2−2x(a−b)+(a+b)2+y2−2y(a+b)
⇒2x(a−b−a−b)=2y(b−a−a−b)
⇒−4bx=−4ay⇒bx−ay=0