Question

X+iy = cisalpha cis beta then x^2+y^2

Answer 1

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Answer 2

x+iy = cisalpha.cisbeta

x+it = ( cosalpha +isinbeta).(cosbeta+isinbeta)

Mod(x+iy) = mod(cosalpha +isinalpha).mod(cosbeta+isinbeta)

√x^2 +y^2 = (√cos^2 alpha +sin^2alpha)(√cos^2 beta + sin^2 beta)

We know that, sin^2 x+cos^2x = 1

√x^2 +y^2 = (1)(1)

√x^2 + y^2 =1

Squaring both sides

x^2 + y^2 = 1