Let z = 3( cos pi/2 + i sin pi/2). Find the exact value of z^7 where 0 (less than equal to) theta (less than equal to) 2pi. Find (-3sqrt2/2 - 3sqrt2/2 i)^5 Find the three cube roots of 216(cos315° + i sin315°) Find the two square roots -8 - 8sqrt3i. Solve z^3 = 27i for all three roots Find all three cube roots of 8(cos pi + i sin pi)

Taniya Melton

Taniya Melton

Answered question

2022-10-29

Let z = 3 ( cos π / 2 + i sin π / 2 ). Find the exact value of z 7 where 0 (less than equal to) theta (less than equal to) 2 π.
Find ( 3 2 2 3 2 2 i ) 5
Find the three cube roots of 216 ( cos 315 ° + i sin 315 ° )
Find the two square roots 8 8 3 i.
Solve z 3 = 27 i for all three roots
Find all three cube roots of 8 ( cos π + i sin π )

Answer & Explanation

Sauppypefpg

Sauppypefpg

Beginner2022-10-30Added 23 answers

Let z = 3 ( cos ( π 2 ) + i sin ( π 2 ) ) exact value of z 7 . Where 0 θ 2 π
Solution
z 7 = [ 3 ( cos ( π 2 ) ) ] 7 z 7 = ( 3 ) 7 [ cos ( π 2 ) + i sin ( π 2 ) ] 7
Use de-moiver Theorem
z = [ cos θ + i sin θ ] n = [ cos n θ + i sin ( n θ ) ] z 7 = 2187 [ cos ( 7 π 2 ) + i sin ( 7 π 2 ) ] z 7 = 2187 [ 0 + i sin ( 3 π + π 2 ) ] z 7 = 2187 [ 0 + i sin ( π 2 ) ] = 2187 [ 0 + i × 1 ] z 7 = 2187 i

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