# Problems with the tangent plane

## Question 4

Consider the
function **f(x,y)=(1/y-x)** Use GraphTan to plot the tangentplane to this
function at (x0,y0)=(1,0).

Why won't it plot? What is the geometric significance of
this?

## Question 5

Consider the sphere from question 2:
**F(s,t)=(cos(s)cos(t), sin(s)cos(t), sin(t)), s=0..2*Pi,t=0..2*Pi**

Use the ParamTan command to plot the tangent plane at (s0,t0)=[0,Pi/2]

Why is there no plane at the point? What does this mean geometrically?

Next: **Applications of the Tangent Plane**
Back: **Tangent Planes to Implicit Functions**