Calculus

Lesson 36

Arc Length and Surface Area

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                        Recall from Pythagorean theorem (or distance formula):

 

                                    Length of a line:      

 

 

 

                                    Taking this to the limit of differentials:

 

 

                                                                       

 

 

 

So arc length is typically found by: 

 

 

 

                                    Examples: 

 

 

 

 

 

                                    Surface Area:  the strip is not a rectangle of differential width, but rather

                                    is a trapezoid, so we don't use dx, but rather ds!

 

 

                                               

 

 

 

                                    So length is like a thin sliver of a cylinder, with radius p, so length is 2pp. 

 

 

                                    The differential width is ds.

 

 

 

 

 

 

 

 

                                    Examples:       about both x and y  (for y, use g(y)).

 

 

On to Lesson 37 - Work

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