Hi everyone! I have two questions, one about area of surface of revolution and another is about arc length...(adsbygoogle = window.adsbygoogle || []).push({});

I really fail to do this two question despite many times of trying so I hope someone can help me

1. Find the area of the surface of revolution generated by revolving the arc of the cardioid " x = 2 cos θ - cos 2θ, y = 2 sin θ - sin 2θ " about the X-axis.

2. A warehouse is 75m long and 40m wide. A cross-section of the roof is the inverted catenary y = 31 - 10 (e^0.05x + e^-0.05x). Find the number of square metres of roofing in the warehouse. Hint: Find the arc length of the catenary and multiply this by the length of the warehouse.

I would be really grateful if you can help me!

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Arc length & area of surface of revolution

**Physics Forums | Science Articles, Homework Help, Discussion**