# Finding the tangent line

1. Mar 12, 2009

### ƒ(x)

Find the equation for the line that is tangent to the given formula if y = pi/2 when x = 0

2. Relevant equations

(x+1)dy - [(1/2)secycscy]dx = 0

3. The attempt at a solution

I tried to do this, and I got that

dy/dx = 1 / (0*0), which is infinity.

So....

y = $$\infty$$?

2. Mar 12, 2009

### Tom Mattson

Staff Emeritus
OK, so the slope is undefined. What kind of line has a slope that's undefined?

3. Mar 12, 2009

### ƒ(x)

So it's a vertical line and no longer a function. That's the answer?

4. Mar 13, 2009

### HallsofIvy

Staff Emeritus
Your original problem was to find the tangent line. Nothing was said about being a function. What is the equation of the vertical line through (0, pi/2)?