# Area for slicing

by icystrike
Tags: slicing
 P: 436 Can i ask what is the area we are refering to when we take such integral (r is the radius): $$\int_{-\infty }^{\infty }e^{-r^{2}}dr$$ I'm suspecting that its is the area of slices of bell curve that rotates about the z-axis. Attached Thumbnails
 Sci Advisor HW Helper Thanks P: 26,148 hi icystrike! it's the integral of a vertical slice of the bell curve through its centre
 Math Emeritus Sci Advisor Thanks PF Gold P: 39,682 You understand, I hope, that finding area is one possible application of the integral. When we calculate an integral we are not necessarily finding any area at all!
 P: 436 Area for slicing Thanks tiny-tim and HallsofIvy! Yes! I know that! We can use Integral to compute things like work, flux, centroids .. =D Its just that my teacher actually relate the slice as "some slice that is parallel to the y-axis" while i think that it should be the slice that is passing through origin(He've probably made some mistake)... (My teacher was actually comparing the volume of a rotated bell curve about z axis by slice and shells to evaluate the area under bell curve - $$A^{2}=\pi$$ )