Question

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Z1 = 4cis (pi/2) and Z2=3cis(3pi/2)
The product of Z1 and Z2 is

Answer 1

Answer:

z₁ × z₂ = 12·cis(2·π)

Step-by-step explanation:

z₁ = 4·cis(π/2), z₂ = 3·cis(3·π/2)

We have;

z₁ = 4·cis(π/2) = 4·(cos(π/2) + i·sin(π/2))

z₂ = 3·cis(3·π/2) = 3·(cos(3·π/2) + i·sin(3·π/2))

According to De Moivre's Theorem,

z₁ × z₂ = 4×3×(cos(π/2 + 3·π/2) + i·sin(π/2 + 3·π/2)) = 12·(cos(2·π) + i·sin(2·π))

∴ z₁ × z₂ = 12·cis(2·π)