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Find the value of 'p' sucj that the function f(z) expressed in polar co-ordinates as f(z) = r3 cos p&theta
1 Answer
written 3.9 years ago by |
Answer:Given function f(z)=r3cospθ+irpsin3θ. Comparing it with the standard complex function f(z)=u+iv.
Here, u=r3cospθ,v=rpsin3θ.
If the function is analytic, it should satisfy Cauchy-Reimann equation, i.e.,
∂u∂r=1r∂v∂θ.................(1)
∂u∂θ=−r∂v∂r..................(2)
Now from (1), 3r2cospθ=3rrpcos3θ or, 3r2cospθ=3rp−1cos3θ⇒p=3(∵r2=rp−1⇒p−1=2⇒p=3,cospθ=cos3θ⇒p=3)
From (2), −r3psinpθ=−rprp−1sin3θ or r2sinpθ=rp−1sin3θ ⇒p=3(∵r2=rp−1⇒p=3,sinpθ=sin3θ⇒p=3)
Thus p=3. Answer.