Question: The area of the region bounded by the locus of a point P satisfying $ d(P,A)=4 $ , where A is (1, 2) is
Options:
A) 64 sq. unit
B) 54 sq. unit
C) $ 16\pi sq.unit $
D) None of these
Show Answer
Answer:
Correct Answer: A
Solution:
- [a] We have, max $ {| x-1 |,| y-2 |}=4 $
If $ {| x-1 |\ge | y-2 |}, $
then $ | x-1 |=4, $
i.e., if $ (x+y-3)(x-y+1)\ge 0, $
Then $ x=-3or5, $
If $ | y-2 |\ge | x-1 |, $
Then $ | y-2 |=4 $
i.e., $ (x+y-3)(x-y+1)\le 0, $
Then $ y=-2or6. $
So, the locus of P bounds a square, the equation of whose sides are $ x=-3,x=5,y=-2,y=6 $
Thus, the area is $ {{(8)}^{2}}=64. $