x= a + b, y = aa + bß and z= aß + ba, where a and ß are complex cube roots of unity, then what is the value of xyz?
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Answer:
Step-by-step explanation:
let complex cubes of unity be w and w²
Therefore w³=1
and 1+w²+w = 0 => w+w²= -1
x=a+b
y= wa+w²b
z= w²a+wb
Now y*z = (wa+w²b)*(w²a+wb)
= w³a² + w²ab + w⁴ab + w³b²
= a² + ab(w²+w) + b²
= a² - ab + b²
Now xyz = (a+b)(a²-ab+b²) = a³+b³
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