# Area of a surface of revolution around the x-axis

1. Sep 22, 2009

### Bachelier

Can the Surface area of a revolution be NEGATIVE? I am calculating this in parametric equations?

finally I hope this is the right forum to ask this question.

2. Sep 22, 2009

### sylas

Yes.

It is quite common for negative areas to show up in some context when you distinguish the inside and the outside of a surface. Depending on how you set up the formulae, you may have a case like this. Depending on what you are trying to find, you may need to alter the formula.

Cheers -- sylas