Tangent Line to Curve of Intersection: Calculating the Normal and Cross Product

In summary, the problem asks for parametric equations for the tangent line to the curve of intersection of a cone and a plane at a specific point. The attempt at a solution involves trying to make the two equations equal to each other and solving for x or y, but this approach does not work. Instead, the suggestion is to use the fact that the curve of intersection lies in both surfaces and to calculate the normals at a point on the curve, which can then be used to find the tangent line.
  • #1
Yitin
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Homework Statement



Find parametric equations for the tangent line to the curve of intersection of the cone z=√(x2 + 4y2) and the plane 3z = x + 2y + 8 at the point (3,2,5)

2. The attempt at a solution

I was trying to make the two Zs equal to each other, and solve for x or y, but I couldn't get any of them separate. I tried squaring both of them so they would both have things like X2. It didn't work out.
 
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  • #2
Yitin said:

Homework Statement



Find parametric equations for the tangent line to the curve of intersection of the cone z=√(x2 + 4y2) and the plane 3z = x + 2y + 8 at the point (3,2,5)

2. The attempt at a solution

I was trying to make the two Zs equal to each other, and solve for x or y, but I couldn't get any of them separate. I tried squaring both of them so they would both have things like X2. It didn't work out.

That's enough reason to try a different approach. Remember that the curve of intersection of two surfaces lies in both surfaces. So if you calculate the normal to each surface at a point on the surface, each normal will be perpendicular to the curve at that point. So the cross product of the normals will be tangent to the curve. And gradients are perpendicular to surfaces...
 

1. What is the "curve of intersection"?

The curve of intersection is the curve formed by the intersection of two surfaces or objects in a three-dimensional space. It is the set of points where the two surfaces or objects meet.

2. How is the curve of intersection calculated?

The curve of intersection can be calculated by finding the points of intersection between the two surfaces or objects using algebraic equations or by graphically plotting the two surfaces and finding their intersection.

3. What is the significance of the curve of intersection in science?

The curve of intersection is important in many fields of science, such as mathematics, physics, and engineering. It helps to visualize and understand the relationship between two objects or surfaces and can provide valuable information about their properties and interactions.

4. Can the curve of intersection be a straight line?

Yes, the curve of intersection can be a straight line if the two surfaces or objects are parallel or if they intersect at a constant angle. In some cases, the curve of intersection can also be a point or a plane.

5. How does the curve of intersection relate to real-world applications?

The curve of intersection has various applications in real-world scenarios. For example, it is used in computer graphics to create 3D models, in architecture to design and construct buildings, and in physics to understand the behavior of light and other electromagnetic waves.

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