Consider the function on three variables defined as . Let be the twisted cubic polynomial curve given by as moves from 0 to 1. What is the value of
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
Each component of F is given in terms of the x, y, and z components of r ( t ) . i.e., the x-component of F is the product of the x and y components of r ( t ) , the y-component of F is the product of the y and z components of r ( t ) , and the z-component of F is the product of the z and x components of r ( t ) . So our line integral is: N = ∫ C F ⋅ d r = ∫ C F ( r ( t ) ) ⋅ r ′ ( t ) d t = ∫ C ( ( t ⋅ t 2 ) , ( t 2 ⋅ t 3 ) , ( t 3 ⋅ t ) ) ⋅ ( 1 , 2 t , 3 t 2 ) d t = ∫ C ( t 3 , t 5 , t 4 ) ⋅ ( 1 , 2 t , 3 t 2 ) d t Taking the dot product and integrating from 0 to 1: ⇒ ∫ 0 1 ( t 3 + 5 t 6 ) d t = [ 4 1 t 4 + 7 5 t 7 ] 0 1 = 2 8 2 7 ≈ 0 . 9 6 4 3