InterviewSolution
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InterviewSolution
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Suppose is a positive real number such that `a^(5)-a^(3)+a=2`. ThenA. `a^(6)lt2`B. `2lt a^(6)lt3`C. `3lt a^(6)lt4`D. `4lea^(6)` |
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Answer» Correct Answer - c `a^(5)-a^(3)a=2,aepsilonR^(+)` `Let f(a)=a^(5)-a^(3)+a-2, {"Note f"(a) gt0AAa in R}` `"for"a^(6)=3Rightarrowa=3^(1//6)=1.2 {"use calculator"}` `"we get" f(1.2)lt 0 and at a=4^(1//6)RightarrowF(4^(1//6))gt0` so one root in a `in (3,4)` |
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