6. What point on the y-axis is equidistant from P(0.8
and Q (-4, 4)?
Answers
hope you got it the answer .........
Answer:
istance formula:
Distance between two points (a,b) and (c,d) is given by :-
\sqrt{(d-b)^2+(c-a)^2}
(d−b)
2
+(c−a)
2
Let O(0,y) be the point on the y-axis.
Distance between P(0,8) and O(0,y): PO=\sqrt{(y-8)^2+(0)^2}=y-8PO=
(y−8)
2
+(0)
2
=y−8
Distance between Q(-4,4) and O(0,y): QO=\sqrt{(y-4)^2+(0-(-4))^2}=y-8QO=
(y−4)
2
+(0−(−4))
2
=y−8
=\sqrt{(y-4)^2+16}=
(y−4)
2
+16
As per given , O is equidistant from p(0,8) and Q(-4,4)..
⇒ PO=QO
y-8=\sqrt{(y-4)^2+16}y−8=
(y−4)
2
+16
Squaring on both sides , we get
(y-8)^2=(y-4)^2+16(y−8)
2
=(y−4)
2
+16
y^2-16y+64=y^2-8y+16+16\ \ [\because\ (a-b)^2=a^2-2ab+b^2]y
2
−16y+64=y
2
−8y+16+16 [∵ (a−b)
2
=a
2
−2ab+b
2
]
-16y+8y=32-64−16y+8y=32−64
\begin{gathered}-8y=-32\\\\\Rightarrow\ y=\dfrac{32}{8}=4\end{gathered}
−8y=−32
⇒ y=
8
32
=4
Hence, the point on the y-axis is equidistant from P(0,8) and Q(-4,4) is (0,4).