# Vector Equation, Parametric Equations and Symmetric Equation Passing Through Two Points (3D)

This video explains how to find the vector equation, parametric equations, and symmetric equations of a line passing through 2 points in space.

# Convert a Rectangular Equation to a Spherical Equation x^2+y^2-z^2=0

This video explains how to convert a rectangular equation (cone) to a spherical equation.

# Convert a Rectangular Equation to a Spherical Equation x^2+y^2+z^2-9z=0

This video explains how to convert a rectangular equation (sphere) to a spherical equation.

# Convert a Spherical Equation to a Rectangular Equation phi=pi/6

This video explains how to convert an spherical equation to a rectangular equation.

# Convert a Spherical Equation to a Rectangular Equation rho=2csc(phi)

This video explains how to convert an spherical equation to a rectangular equation.

# Show the Gradient to a Surface Using 3D Calc Plotter

This video using 3D Calc Plotter to illustrate the meaning of a gradient vector.

# Show Tangent Lines to a Surface Using 3D Calc Plotter – Directional Derivative

This video using 3D Calc Plotter to illustrate the meaning of a directional derivative.