Consider the complex number z=−33−3i.What is z3 ?Hint: z has a modulus of 6 and an argument of 210∘.Choose 1 answer:(A) −216i(B) −216(C) −108+187.1i(D) 108+187.1i
Q. Consider the complex number z=−33−3i.What is z3 ?Hint: z has a modulus of 6 and an argument of 210∘.Choose 1 answer:(A) −216i(B) −216(C) −108+187.1i(D) 108+187.1i
Identify modulus and argument: Identify the modulus and argument of the complex number z. Given z=−33−3i, we are told that the modulus of z is 6 and the argument is 210 degrees. This information will be used to find z3 using the polar form of the complex number.
Convert to polar form: Convert the complex number z to its polar form. The polar form of a complex number is given by z=r(cos(θ)+isin(θ)), where r is the modulus and θ is the argument. For z, we have r=6 and θ=210 degrees. Therefore, the polar form of z is z=6(cos(210°)+isin(210°)).
Use De Moivre's Theorem: Use De Moivre's Theorem to find z3. De Moivre's Theorem states that (r(cos(θ)+isin(θ)))n=rn(cos(nθ)+isin(nθ)). We want to find z3, so we will raise the polar form of z to the power of 3.
Calculate z3: Calculate z3 using De Moivre's Theorem.We have z3=(6(cos(210°)+isin(210°)))3=63(cos(3⋅210°)+isin(3⋅210°))=216(cos(630°)+isin(630°)).
Simplify trigonometric functions: Simplify the trigonometric functions.Since 630° is equivalent to 270° (as 630°−360°=270°), we can simplify the expression to 216(cos(270°)+isin(270°)). The cosine of 270° is 0, and the sine of 270° is −1. Therefore, z3=216(0−i)=−216i.