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MCS 351 ENGINEERING MATHEMATICS SOLUTION OF ...

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Hence we get x(t) = −a + r cos t, y(t) = −b + r sin t, −2π ≤ t ≤ 0.<br />

18. 4(x − 1) 2 + 9(y + 2) 2 = 36 denotes an ellips.<br />

Hence we get ellips below:<br />

4(x − 1) 2 + 9(y + 2) 2 = 36 ⇒ ( x − 1 ) 2 + ( y + 2<br />

3 2 )2 = 1<br />

x 0 − 1 = 0, y 0 + 2 = 0 ⇒ x 0 = 1, y 0 = −2 ⇒ z 0 = (1, −2)<br />

Parametric equation: x(t) = 3 cos t + 1, y(t) = 2 sin t − 2, 0 ≤ y ≤ 2π<br />

19-29 Integration:<br />

19. Let z = x + iy. Then f(z) = Rez = x is analytic in C. So we can use the first method:<br />

∫ z1<br />

z 0<br />

f(z)dz = F (z 1 ) − F (z 0 ), F (z) analytic, F ′ (z) = f(z)<br />

Let F (z) = x2<br />

2 . F ′ (z) = 2 x 2 = x = f(x).<br />

∫ 1+i<br />

20. We can sketch C as follows:<br />

0<br />

f(z)dz =<br />

∫ 1+i<br />

0<br />

xdz = F (1 + i) − F (0) = 1 2<br />

If z = x + iy, then f(z) = Rez = x is analytic in C. So we can use the first method.<br />

F (z) = x2<br />

2 is analytic in C and F ′ (z) = 2 x 2 = x = f(x).<br />

∫ ∫ 1+i ∫ 1+i<br />

Rez = f(z)dz = xdz = F (1 + i) − F (0) = 1 2<br />

C<br />

21.<br />

31<br />

0<br />

0

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