a)Find the equation of the tangent plane to the graph z = x2 + 4y2 at the point (a, b, a2 + 4b2) b) For what values of a and b is the tangent plane perpendicular to the vector (3, -4, 2)? I figured you have to use the tangent plane equation z - zo = zx(a,b)(x-a) + zy(a,b)(y-b). This gave me the equation Z = 2ax + 8by - a2 - 4b2 For b, I think the dot product could be used if I set it to zero. But how would I go about solving for a and b? I think I may just be getting tired and a bit sloppy, because I know this is already stuff I have gone over, the only new thing is solving for a and b. Any direction on this would be great, I'm just having trouble visualizing this problem.