Find the points on the surface at which the tangent plane is parallel to the plane .
( , , ) and ( , , )
guys, plz help i have no idea how to do this one
guy this is what i have done so far,
<10x, 4y, 10z> = C<-3, 3, 3>
x = -3C/10, y = 3C/4, z = 3C/10
f(x,y,z) = 5x^2+2y^2+5z^2 = 1
= 5(-3C/10)^2 + 2(3C/4)^2 + 5(3C/10)^2 = 1
((9C^2)/20)+((9C^2)/8)+((9C^2)/20) = 1
((81C^2)/20) =1,,,,,,, C = .7027
i don't know what do from here