Question

Find an equation of the largest sphere with center (5,4,9) that is contained in the first octant.

Answer 1

say what?

Answer 2

and r^2 is what?

Answer 3

hold on

Answer 4

(5,4,9)

we can't touch any coordinate plane so if radius >4 we will touch y plane

Answer 5

so r can't be bigger that 4 , r^2 can't be bigger than 16

Answer 6

okay..so how do i go about solving this then?

Answer 7

this was a question on my first test that i didn't get right lol

Answer 8

your sphere is just
(x-5)^2+(y-4)^2+(z-9)^2=16

Answer 9

http://www.wolframalpha.com/input/?i=ContourPlot3D%5B(x%20-%205)%5E2%20%2B%20(y%20-%204)%5E2%20%2B%20(z%20-%209)%5E2%20%3D%3D%20(16)%2C%20%7Bx%2C%200%2C%20%20%20%2010%7D%2C%20%7By%2C%200%2C%2010%7D%2C%20%7Bz%2C%205%2C%2015%7D%5D&t=crmtb01