Convert the given complex number in polar form -1 + i and evaluate

Asked by Abhisek | 1 year ago |  70

1 Answer

Solution :-

The complex number is -1+i

Let rcosθ = -1 and rsinθ = 1

Squaring and adding

\( r^2cos^2θ + r^2sin^2θ = (-1)^2+1^2\)

\( r^2(cos^2θ + sin^2θ) =1+1\)

\( r^2=2\)

\( r=\sqrt{2}\)  

\(\sqrt{2} cosθ = -1 \;and\; \sqrt{2}sinθ = 1\)

\( cosθ =- \dfrac{1}{\sqrt{2}}and \sqrt{2}sinθ =1\)

\( θ ...(\pi-\dfrac{\pi}{4})...-\dfrac{3\pi}{4}L\) [As θ lies in the II quadrant]

It can be written,

-1+i = rcosθ + irsinθ 

=\(\sqrt{2}cos \dfrac{3\pi}{4}+i\sqrt{2}sin \dfrac{3\pi}{4}\)

\( \sqrt{2}(cos \dfrac{3\pi}{4}+isin \dfrac{3\pi}{4})\)

Answered by Pragya Singh | 1 year ago

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