Question
Mathematics Question on Area between Two Curves
A plane x + 2y + 2z – 15 = 0 cuts a sphere x2 + y2 + z2 – 2y – 4z – 11 = 0 in a circular section. What is the radius of the cut section?
A
(A) √2 units
B
(B) √5 units
C
(C) 3 units
D
(D) √7 units
Answer
(D) √7 units
Explanation
Solution
Explanation:
since, the centre of sphere x2+y2+z2−2y−4z−11=0 is (0,1,2) andradius is 4∴ Distance of a plane x+2y+2z−15=0from (0,1,2)=|0+2+4−15|1+4+4=93=3=42−32=16−9=7Radius of circle =7