1.

Let p, q, r `in` R and `r gt p gt 0`. If the quadratic equation `px^(2) + qx + r = 0` has two complex roots `alpha and beta`, then `|alpha|+|beta|`, isA. less than 2 but not equat to 1B. equal to 2C. equal to 1D. greater than 2

Answer» Correct Answer - D
Since `alpha and beta` are complex conjugate of each other.
`therefore" "alpha = bar(beta) and , bar(alpha) = beta rArr |alpha| = |beta|`
Now, `alpha = bar(beta) rArr alpha beta = bar(beta)beta rArr alpha beta = |beta|^(2)`
Now, `alpha beta = (r)/(p) rArr |alpha|^(2) = |beta|^(2) = (r)/(p) gt 1 rArr |alpha| = |beta| gt 1`
Hence, `|alpha|+|beta| gt 2`.


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