- #1
jimmy42
- 51
- 0
I have the vector:
[tex]{\bf{u}}(x,y) = \frac{{x{\bf{i}} + y{\bf{j}}}}{{{x^2} + {y^2}}}[/tex]
Where:
[tex]x = a\cos t[/tex] [tex]y = a\sin t[/tex]
I know I need to use the equation
[tex]\int\limits_0^{2\pi } {{\bf{u}} \cdot d{\bf{r}}} [/tex]
And the answer is
[tex]\int\limits_0^{2\pi } {} ((a\cos t/{a^2})( - a\sin t) + (a\sin t/{a^2})(a\cos t)dt = 0[/tex]
The trouble I have is finding that [tex]{d{\bf{r}}}[/tex] How is that done? Can someone help?
[tex]{\bf{u}}(x,y) = \frac{{x{\bf{i}} + y{\bf{j}}}}{{{x^2} + {y^2}}}[/tex]
Where:
[tex]x = a\cos t[/tex] [tex]y = a\sin t[/tex]
I know I need to use the equation
[tex]\int\limits_0^{2\pi } {{\bf{u}} \cdot d{\bf{r}}} [/tex]
And the answer is
[tex]\int\limits_0^{2\pi } {} ((a\cos t/{a^2})( - a\sin t) + (a\sin t/{a^2})(a\cos t)dt = 0[/tex]
The trouble I have is finding that [tex]{d{\bf{r}}}[/tex] How is that done? Can someone help?