Q. Find all of the cube roots of −1 and write the answers in rectangular (standard) form.Answer Attempt 2 out of 2
Identify Equation: Identify the equation for finding cube roots of a number.To find the cube roots of −1, we solve the equation x3=−1.
Convert to Polar Form: Convert the equation into polar form to facilitate finding roots.The number −1 can be represented in polar form as 1∗(cos(π)+i∗sin(π)).
Apply De Moivre's Theorem: Apply De Moivre's Theorem to find the cube roots.Using De Moivre's Theorem, the nth roots (n=3 here) of a complex number r(cos(θ) + i*sin(θ)) are given by:r1/n(cos(nθ+2kπ)+isin(nθ+2kπ))for k = 0, 1, ..., n−1.
Calculate First Root: Calculate the first root (k=0).Plug k=0 into the formula:11/3(cos(3π+2∗0∗π)+isin(3π+2∗0∗π))= cos(π/3) + i*sin(π/3)= 1/2 + i*√3/2
Calculate Second Root: Calculate the second root (k=1).Plug k=1 into the formula:11/3(cos(3π+2∗1∗π)+isin(3π+2∗1∗π))= cos(π) + i*sin(π)= −1 + i*0
Calculate Third Root: Calculate the third root (k=2).Plug k=2 into the formula:11/3(cos(3π+2∗2∗π)+isin(3π+2∗2∗π))= cos(5π/3) + i*sin(5π/3)= 1/2 - i*√3/2