English

If ω is a complex cube root of unity, show that (a − b) (a − bω) (a − bω2) = a3 − b3

Advertisements
Advertisements

Question

If ω is a complex cube root of unity, show that (a − b) (a − bω) (a − bω2) = a3 − b3

Sum
Advertisements

Solution

ω is the complex cube root of unity

∴ ω3 = 1 and 1 + ω + ω2 = 0

Also, 1 + ω2 = − ω, 1 + ω = − ω2 and ω + ω2 = − 1

L.H.S. = (a − b)(a − bω)(a − bω2)

= (a − b) (a2 − abω2 − abω + b2ω3)

= (a − b) [a2 − ab(ω2 + ω) + b2(1)]

= (a − b) [a2 − ab(−1) + b2]

= (a − b) (a2 + ab + b2)

= a3 − b3

= R.H.S.

shaalaa.com
  Is there an error in this question or solution?
Chapter 1: Complex Numbers - Exercise 1.4 [Page 20]

RELATED QUESTIONS

If `omega` is a complex cube root of unity, show that `(2 - omega)(2 - omega^2)` = 7


If ω is a complex cube root of unity, show that (2 + ω + ω2)3 - (1 - 3ω + ω2)3 = 65


If ω is a complex cube root of unity, find the value of ω2 + ω3 + ω4.


If x = a + b, y = αa + βb and z = aβ + bα, where α and β are the complex cube roots of unity, show that xyz = a3 + b3.


If ω is a complex cube root of unity, then prove the following:  (a + b) + (aω + bω2) + (aω2 + bω) = 0.


Find the value of ω18


Find the value of ω21


Find the value of ω–30


If ω is a complex cube root of unity, show that (1 + ω)3 − (1 + ω2)3 = 0


If ω is a complex cube root of unity, show that (a + b)2 + (aω + bω2)2 + (aω2 + bω)2 = 6ab


If ω is a complex cube root of unity, find the value of `ω + 1/ω`


If α and β are the complex cube root of unity, show that α2 + β2 + αβ = 0


If α and β are the complex cube root of unity, show that α4 + β4 + α−1β−1 = 0


If , where α and β are the complex cube-roots of unity, show that xyz = a3 + b3.


Find the equation in cartesian coordinates of the locus of z if |z| = 10


Find the equation in cartesian coordinates of the locus of z if |z − 5 + 6i| = 5


Find the equation in cartesian coordinates of the locus of z if |z – 2 – 2i| = |z + 2 + 2i|


If ω(≠1) is a cube root of unity and (1 + ω)7 = A + Bω, then A and B are respectively the numbers ______.


Answer the following:

If ω is a complex cube root of unity, prove that (1 − ω + ω2)6 +(1 + ω − ω2)6 = 128


If (1 + ω2)m = (1 + ω4)m and ω is an imaginary cube root of unity, then least positive integral value of m is ______.


If α, β, γ are the cube roots of p (p < 0), then for any x, y and z, `(xalpha + "y"beta + "z"gamma)/(xbeta + "y"gamma + "z"alpha)` = ______.


If the cube roots of the unity are 1, ω and ω2, then the roots of the equation (x – 1)3 + 8 = 0, are ______.


If w is a complex cube root of unity, show that `((a+bw+cw^2))/(c+aw+bw^2) = w^2`


If w is a complex cube root of unity, show that `((a + bw +cw^2))/(c +aw + bw^2) = w^2`


If w is a complex cube-root of unity, then prove the following:

2 + ω − 1)3 = −8


If w is a complex cube root of unity, show that `((a + bw + cw^2))/(c+aw+bw^2) = w^2`


If w is a complex cube root of unity, show that `((a+bw+cw^2))/(c+aw+bw^2) =w^2`


If ω is a complex cube root of unity, then prove the following.

2 + ω −1)3 = −8


If w is a complex cube root of unity, show that `((a + bω + cω^2))/(c + aω + bω^2) = ω^2`


If ω is a complex cube-root of unity, then prove the following:

2 + ω −1)3 = −8


If w is a complex cube-root of unity, then prove the following

(w2 + w - 1)3 = - 8


If w is a complex cube root of unity, show that `((a+bw+cw^2))/(c+aw+bw^2)=w^2`


If w is a complex cube-root of unity, then prove the following. 

(w+ w - 1)= - 8


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×