Question

Let α, β and γ be the cube roots of p (p < 0). For any real numbers x, y and z, the value of  (xα+yβ+zγ) (xβ+yγ+zα) is

Joshi sir comment

According to the given condition p is a negative number

consider p = -k so cube root of p will be α = -k1/3, β = -k1/3ω, γ = -k1/3ω2

On applying given values you will get the answer as  ω or ω2

you should use ω3 = 1

    

Solution by Joshi sir.

 

According to the given condition p is a negative number

consider p = -k = (k1/3)3(-1) so cube root of p will be α = -k1/3, β = -k1/3ω, γ = -k1/3ω, here -1, -ω, -ω2 are the cube roots of -1

On applying given values on the given expression, you will get  

x(-k1/3)+y(-k1/3ω)+z(-k1/3ω2)/x(-k1/3ω)+y(-k1/3ω2)+z(-k1/3)

=x+yω+zω2/xω+yω2+z

first multiply ω in numerator and denominator we get answer as 1/ω = ω2

second interchange the value of α, β, γ for getting answer as ω

you should use ω3 = 1

    

Read 3 Solution.

lets say p=-1 then its root are -1,-ω,-ω2

so the above eqn has roots p,pω,pω2

now divide and multiply the above equation by ω after that u will find that the above equation get reduced to the form 1/ω . 

therefore the answer is -ω

NIKHIL VARSHNEY 12 year ago is this solution helpfull: 0 0

i don't get the answer. sir, can u please solve it.

HIMANSHU MITTAL 12 year ago is this solution helpfull: 0 0

use p1/3instead of p

1/w=w3/w=w2

NIKHIL VARSHNEY 12 year ago is this solution helpfull: 0 0

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