(1 point) Find an equation of the tangent plane to the parametric surface x=5rcosθx=5rcos⁡θ, y=4rsinθy=4rsin⁡θ, z=rz=r at the point (52–√,42–√,2)(52,42,2) when r=2r=2, θ=π/4θ=π/4. z = Note: Your answer should be an expression of x and y; e. g. "3x - 4y"

Denote the given surface by the vector-valued function,

Then the normal vector to this plane is

When and , the normal vector is

and so the equation of the tangent plane is

Judging by the "note", you need to write the equation as , which is trivial:

correct choice is b

step-by-step explanation:

when you calculate the average rate of change of a function, you are finding the slope of the secant line between the two points. for the function the average rate of change from point to point can be calculated as

to find the average rate of change from day 2 to day 10, note that at day 2, 8 houses were sold, so a(2,8) and at day 10, 2 houses were sold, so b(10,2). thus,

i believe the answer is c.