Step 1: Parameterize the line segment C.
The line segment goes from (x0,y0)=(0,2) to (x1,y1)=(1,4).
A parameterization for a line segment is given by:
x(t)=x0+(x1−x0)t
y(t)=y0+(y1−y0)t
for 0≤t≤1.
Substitute the given points:
x(t)=0+(1−0)t=t
y(t)=2+(4−2)t=2+2t
So, x=t and y=2+2t for 0≤t≤1.
Step 2: Find dx and dy in terms of t.
Differentiate x(t) and y(t) with respect to t:
dtdx=dtd(t)=1⟹dx=dt
dtdy=dtd(2+2t)=2⟹dy=2dt
Step 3: Substitute x, y, dx, and dy into the integral.
The integral is ∫Csin(πy)dy+yx2dx.
Substitute x=t, y=2+2t, dx=dt, dy=2dt:
sin(πy)dy=sin(π(2+2t))(2dt)
Using the periodicity of the sine function, sin(2π+θ)=sin(θ):
sin(π(2+2t))=sin(2π+2πt)=sin(2πt)
So, the first term becomes 2sin(2πt)dt.
The second term is yx2dx:
yx2dx=(2+2t)(t2)dt=(2t2+2t3)dt
Now, substitute these into the integral, changing the limits of integration from t=0 to t=1:
∫01(2sin(2πt)dt+(2t2+2t3)dt)
∫01(2t3+2t2+2sin(2πt))dt
Step 4: Evaluate the definite integral.
Integrate each term with respect to t:
∫(2t3+2t2+2sin(2πt))dt=42t4+32t3+2(−2πcos(2πt))+C
=2t4+32t3−πcos(2πt)+C
Now, evaluate the definite integral from t=0 to t=1:
[2t4+32t3−πcos(2πt)]01
=(2(1)4+32(1)3−πcos(2π(1)))−(2(0)4+32(0)3−πcos(2π(0)))
=(21+32−πcos(2π))−(0+0−πcos(0))
Since cos(2π)=1 and cos(0)=1:
=(21+32−π1)−(−π1)
=21+32−π1+π1
=21+32
To add these fractions, find a common denominator, which is 6:
=63+64
=67
The value of the line integral is 67.