## Application of line integral in an exercise

Hello, can someone help me with this exercise ?

Compute the work done by the force field F(r, θ) = (−4sinθ, 4sinθ) (given inpolar coordinates) in moving a particle along the curve r = e−θfrom (1,0) to the origin.

I'm doing the line integral using the formula of the line integral so Work= c F · ds =ab F(c(t)) · c'(t)dt
and I have 10 (-4sin(t),4sin(t)) · (-4cos(t),4cos(t)) dt so now when I compute it I get 16 and the result should be 8/5