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Question Number 73964 by arkanmath7@gmail.com last updated on 17/Nov/19

if Im(f ′(z)) =6x(2y−1) and   f(0)=3−2i , f(1)=6−5i   find f(1+i)?

ifIm(f(z))=6x(2y1)andf(0)=32i,f(1)=65ifindf(1+i)?

Answered by mind is power last updated on 17/Nov/19

f′(z) is (df/dz)..?

f(z)isdfdz..?

Commented by arkanmath7@gmail.com last updated on 17/Nov/19

yes

yes

Answered by mind is power last updated on 17/Nov/19

f(x+iy)=p(x,y)+iQ(x,y)  f′(z)=(∂/∂z)(f(z))  (∂/∂z)=(1/2)((∂/∂x)−i(∂/∂y))=(1/2)((∂p/∂x)+(∂Q/∂p))−(i/2)((∂p/∂y)−(∂Q/∂x))  Im(f′(z))=imf′(x+iy)=(1/2)((∂Q/∂x)−(∂p/∂y))=6x(2y−1).....E  f holomorphic⇒(∂p/∂x)+i(∂Q/∂x)=−i(∂p/∂y)+(∂Q/∂y)  ⇒(∂Q/∂x)=−(∂P/∂y)⇒E(∂Q/∂x)=12xy−6x⇒Q(x,y)=6x^2 y−3x^2 +H(y)  ⇒P(x,y)=−6xy^2 +6xy+f(x)  (∂p/∂x)=(∂Q/∂y)⇔−6y^2 +6y+f′(x)=6x^2 +H′(y)  ⇒f′(x)=6x^2 ⇒f(x)=2x^3 +c  H′(y)=−6y^2 +6y⇒H(y)=−2y^3 +3y^2 +d  ⇒f(x+iy)=(−6xy^2 +6xy+2x^3 +c)+i(6x^2 y−3x^2 −2y^3 +3y^2 +d)  f(1)=6−5i,  f(0)=3−2i⇒c=3,d=−2  f(1)=(2+3)+i(−3−2)=5−5i  f did′nt exist withe this conditions

f(x+iy)=p(x,y)+iQ(x,y)f(z)=z(f(z))z=12(xiy)=12(px+Qp)i2(pyQx)Im(f(z))=imf(x+iy)=12(Qxpy)=6x(2y1).....Efholomorphicpx+iQx=ipy+QyQx=PyEQx=12xy6xQ(x,y)=6x2y3x2+H(y)P(x,y)=6xy2+6xy+f(x)px=Qy6y2+6y+f(x)=6x2+H(y)f(x)=6x2f(x)=2x3+cH(y)=6y2+6yH(y)=2y3+3y2+df(x+iy)=(6xy2+6xy+2x3+c)+i(6x2y3x22y3+3y2+d)f(1)=65i,f(0)=32ic=3,d=2f(1)=(2+3)+i(32)=55ifdidntexistwithethisconditions

Commented by arkanmath7@gmail.com last updated on 18/Nov/19

thmx sir

thmxsir

Commented by mind is power last updated on 18/Nov/19

y′re welcom

yrewelcom

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