She’ll have to make 4 more stitches in order to get 6 good ones. Each time she creates 3 she undoes 2 which after 4 more times would leave her with 6 good stitches.
Answer:
The integral
is 0.
Step-by-step explanation:
A parameterization of curve C can be:
X (t) = cost 0 <= t <= pi
Y (t) = sint 0 <= t <= pi
r (t) = costi + sintj
r '(t) = -sinti + costj
![Fds = [-costsin^3t + sintcos^3t] dt](https://tex.z-dn.net/?f=Fds%20%3D%20%5B-costsin%5E3t%20%2B%20sintcos%5E3t%5D%20dt)
The integral
is given by:
![\int _0^{\pi }\left[-costsin^3t + sintcos^3t dt\right]dt](https://tex.z-dn.net/?f=%5Cint%20_0%5E%7B%5Cpi%20%7D%5Cleft%5B-costsin%5E3t%20%2B%20sintcos%5E3t%20dt%5Cright%5Ddt)

Not sure if the equation is

or








On the other side of the equation, we'd get

Then

- If it's the second one instead, you can use the same strategy as above:


(Note that this step assume
)



Then we get

There is a 35% chance the first one will not work, and a 49% the second one will not work. (Theoretically there is an 81% chance neither of them will work.)