1.

If `alpha` and `beta`are the roots of `x^(2) - (a+1)x + 1/2 (a^(2) + a+1) = 0` then `alpha^(2) + beta^(2) = "_____"`.A. A and BB. `a^(2)`C. 2aD. 1

Answer» Correct Answer - A
`x^(2) - (a+1)x + 1/2 (a^(2) + a + 1) = 0`
`alpha + beta = a+1`
`alpha beta = 1/2 (a^(2) + a + 1)`
`alpha^(2) + beta^(2) = (alpha + beta)^(2) - 2alphabeta`
`= (a+1)^(2) - 2[1/2(a^(2) +a+1)]`
`= a^(2) + 2a + 1 - a^(2) - a - 1 = a`.


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