Q.
If ω is cube root of unity and x+y+z=a, x+ωy+ω2z=b, x+ω2y+ωz=c then which of the following is correct
see full answer
Start JEE / NEET / Foundation preparation at rupees 99/day !!
21% of IItians & 23% of AIIMS delhi doctors are from Sri Chaitanya institute !!
An Intiative by Sri Chaitanya
a
x=a+b+c3
b
y=a+bω2+ωc3
c
z=a+bω+ω2c3
d
All the above
answer is D.
(Unlock A.I Detailed Solution for FREE)
Ready to Test Your Skills?
Check your Performance Today with our Free Mock Test used by Toppers!
Take Free Test
Detailed Solution
The determinant of the coefficient matrix is Δ=1111ωω21ω2ω=1ω2-ω4-1ω-ω2+1ω2-ω=3ω2-ω ∵ω4=ω Also Δ1=a11bωω2cω2ω=aω2-ω4-bω-ω2+cω2-ω=a+b+cω2-ω Δ2=1a11bω21cω=1bω-cω2-1aω-c+1aω2-cb=a+bω2+cωω2-ω and Δ3=11a1ωb1ω2c=1cω-bω2-1c-aω2+1b-aω=a+bω+cω2ω2-ω ∴By Crammar's rule we have, x=Δ1Δ,y=Δ2Δand z=Δ3Δ. ⇒x=a+b+c3, y=a+bω2+cω3 and z=a+bω+cω23
Watch 3-min video & get full concept clarity