Consider a circle .
Let its mirror image in the line be another circle . Let be the radius of . Then is equal to ______.
Let its mirror image in the line be another circle . Let be the radius of . Then is equal to ______.
Answer: 2
Solution
Completing the square, , so its centre is and radius .
Reflecting the centre in : with , the image centre is .
Writing as with centre , its radius is
A reflection preserves the radius, so , giving . Therefore
Reflecting the centre in : with , the image centre is .
Writing as with centre , its radius is
A reflection preserves the radius, so , giving . Therefore
JEE Main · 2023 · 08 Apr 2023 · Shift 1 · Integer answer