00:01
Hi, in this question, given that the center h, k, l is 3, minus 6, 4 and the radius r equals 5.
00:17
We need to find the equation of the sphere.
00:20
We know that the formula x minus h the whole square plus y minus k the whole square plus z minus l the whole square equals r squared.
00:31
On substituting all the known values in this, then we get x minus 3 the whole square plus y minus minus 6 the whole square plus z minus 4 the whole square equals 5 squared.
00:44
Hence conclude that the equation of the sphere is x minus 3 the whole square plus y plus 6 the whole square plus z minus 4 the whole square equals 25.
00:57
Next move on to part a.
01:01
Here we need to find the intersection with xy plane so that we have to consider z equals 0.
01:16
So we can write it as x minus 3 the whole square plus y plus 6 the whole square plus z is 0.
01:23
So minus 4 the whole square equals 25.
01:27
On further simplified, we get x minus 3 the whole square plus y plus 6 the whole square plus 16 equals 25.
01:37
Therefore, we conclude that the final answer is x minus 3 the whole square plus y plus 6 the whole square equals 25 minus 16 which is 9.
01:47
So which is the answer for intersection xy plane and which is the answer for equation of the sphere...