Let w1 be the point obtained by the rotation of z1=5+4i about the origin through a right angle in the anticlockwise direction, and w2 be the point obtained by the rotation of z2=3+5i about the origin through a ...
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Official solution
To solve the problem, let's break it down step by step.
Find w1:1:Find{w}\_{1}Given{z}\_{1}=5+4i.Whenyourotate{z}\_{1}by{90}\^{\circ }anticlockwiseabouttheorigin,therealpartbecomesnegativeoftheimaginarypartof{z}\_{1},andtheimaginarypartbecomestherealpartof{z}\_{1}.Therefore,{w}\_{1}becomes:{w}\_{1}=-4+5iFind{w}\_{2}: 2 : Find w2
Given z2=3+5i.
When you rotate z2 by 90∘ clockwise about the origin, the real part becomes the imaginary part of z2, and the imaginary part becomes negative of the real part of z2.
Therefore, w2 becomes :
w2=5−3i
Calculate w1−w2:3:Calculate{w}\_{1}-{w}\_{2}{w}\_{1}-{w}\_{2}=(-4+5i)-(5-3i){w}\_{1}-{w}\_{2}=-9+8iFindtheprincipalargumen:4:FindtheprincipalargumentTofindtheprincipalargument,weneedtocomputethetangentinverseoftheratiooftheimaginaryparttotherealpart.Argument={\tan }\^{-1}(\frac{}{})Argument={\tan }\^{-1}(\frac{8}{-9})Argument=-{\tan }\^{-1}(\frac{8}{9})Sinceit′sinthethirdquadrant,theprincipalargumentis:Argument=\pi +(-{\tan }\^{-1}(\frac{8}{9}))Argument=\pi -{\tan }\^{-1}(\frac{8}{9})So,thecorrectoptionis:OptionC: