MCS 351 ENGINEERING MATHEMATICS SOLUTION OF ...
MCS 351 ENGINEERING MATHEMATICS SOLUTION OF ...
MCS 351 ENGINEERING MATHEMATICS SOLUTION OF ...
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g(z) =<br />
sinh πz<br />
z 2 − 3z<br />
=<br />
sinh πz<br />
z(z − 3)<br />
Singular points of g are z 0 = 0 and z 1 = 3. Let D be the union of C and the interior part of C. Then<br />
z 1 = 3 /∈ D but z 0 = 0 ∈ D. f(z) =<br />
we get<br />
12.<br />
∮<br />
C<br />
∮<br />
g(z)dz =<br />
C<br />
sinh πz<br />
z−3<br />
is analytic in D. Hence by use of Cauchy integral formula,<br />
sinh πz<br />
z − 3 .1 0<br />
dz = 2πi.f(0) = 2πisinh<br />
z −3<br />
= 2π sin(i.0) = 0<br />
−3<br />
Let g(z) = tan z<br />
z−i . Singular point z 0 = i is enclosed by C. f(z) = tan z is analytic in D when D is the<br />
union of C and the interior part of C. So by the use of Cauchy integral formula, we get<br />
∮<br />
tan z<br />
dz = 2πi tan i<br />
z − i<br />
13.<br />
C<br />
g(z) = e−3πz 1<br />
2z + i = 2 e−3πz<br />
z + i 2<br />
Singular point z 0 = − i 2 is enclosed by C. f(z) = 1 2 e−3πz is analytic in D when D is the union of C and<br />
the interior part of C. So by use of Cauchy integral formula, we get<br />
∮<br />
e −3πz<br />
1<br />
2z + i<br />
∮C<br />
dz = dz = 2πi. 1 2 e− 3 2 πi =<br />
2 e−3πz<br />
C<br />
z + i 2<br />
15. We sketch C : |z − 4| = 2 as follows:<br />
41<br />
πi<br />
3<br />
2 (cos π + i sin π) = −2 3 πi