Finding Tangent Plane and Normal Line Equations for a Given Surface

In summary, the equations of the tangent plane and the normal line to the given surface at the point (5,3,-3) can be found using the partial derivatives fx, fy, and fz. The equation of the tangent plane is fx(5,3,-3)(x-5) + fy(5,3,-3)(y-3) + fz(5,3,-3)(z-(-3)) = 0. The equation of the normal line is x=10t+5, y=-15t+3, z=-3t-3, where t is a parameter.
  • #1
ktobrien
27
0

Homework Statement


Find equations of the following.

x2-2y2+z2+yz=7, (5,3,-3)
(a) the tangent plane
(b) the normal line to the given surface at the point

Homework Equations



I know it involves fx, fy, fz

The Attempt at a Solution


I got 10x-15y-3z=7. Is this correct? Because its not true at the point (5,3,-3).

I got it by f(5,3,-3)+fx(5,3,-3)(x-5)+fy(5,3,-3)(y-3)+fz(5,3,-3)(z+3)

As for the normal line I know the answers are
x=10t+5
y=-15+3
z=-3-3
 
Last edited:
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  • #2
ktobrien said:

Homework Statement


Find equations of the following.

x2-2y2+z2+yz=7, (5,3,-3)
(a) the tangent plane
(b) the normal line to the given surface at the point

Homework Equations



I know it involves fx, fy, fz

The Attempt at a Solution


I got 10x-15y-3z=7. Is this correct? Because its not true at the point (5,3,-3).
No. The point (5, 3 -3) has to satisfy both the equation of the plane and the equation of the surface.
ktobrien said:
I got it by f(5,3,-3)+fx(5,3,-3)(x-5)+fy(5,3,-3)(y-3)+fz(5,3,-3)(z+3)
For one thing, this is not an equation, so there's no way to get an equation out of it. For another thing, if my memory is correct, the equation of the tangent plane is fx(5, 3, -3)(x - 5) + fy(5, 3, -3)(y - 3) + fz(5, 3, -3)(z - (-3)) = 0.

You didn't show the partial derivatives that you calculated, so it might also be that you have an error in one or more of them.

ktobrien said:
As for the normal line I know the answers are
x=10t+5
y=-15+3
z=-3-3
 
  • #3
Ive got it now. I used the linear approximation and set it = to 0. I just had to take out the f(5,3,-3). I figured it was something stupid like that. Thanks for the help though.
 

What is the equation of the tangent plane?

The equation of the tangent plane is a mathematical representation of a plane that touches a curved surface at a specific point, known as the point of tangency. It is used to approximate the behavior of a surface at that point.

How is the equation of the tangent plane calculated?

The equation of the tangent plane is calculated using the partial derivatives of the function representing the curved surface at the point of tangency. These derivatives are used to find the slope of the tangent line, which is then used to determine the equation of the tangent plane.

What is the purpose of the equation of the tangent plane?

The equation of the tangent plane is used to approximate the behavior of a curved surface at a specific point. It is especially useful in the fields of mathematics, physics, and engineering, where it is used to analyze and solve problems involving curved surfaces.

Can the equation of the tangent plane be applied to any type of surface?

Yes, the equation of the tangent plane can be applied to any type of surface, as long as the surface is differentiable at the point of tangency. This means that the surface must be smooth and continuous at that point.

What other applications does the equation of the tangent plane have?

The equation of the tangent plane has various applications in fields such as computer graphics and computer-aided design (CAD). It is also used in optimization problems, where it helps in finding the maximum or minimum values of a function at a specific point.

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