InterviewSolution
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Statement-1: if `thetane2npi+(pi)/(2),n inZ,` then `(sec^(2)theta+tantheta)/(sec^(2)theta-tantheta)"lies between"1/3 and 3.` Statement-2: If `x inR, then 1/3le(x^(2)-x+1)/(x^(2)+x+1)le3.`A. Statement-1 is True, Statement-2 is true, Statement-2 is a correct explanation for Statement -1.B. Statement-1 is True, Statement-2 is True, Statement-2 is not a correct explanation for Statement-1.C. Statement-1 is True, Statement-2 is False.D. Statement-1 is False, Statement-2 is True. |
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Answer» Correct Answer - A Let `y=(x^(2)-x+1)/(x^(2)+x+1).Then,` `x^(2)(y-1)+x(y+1)+(y-1)=0` `implies(y+1)^(2)-4(y-1)^(2)ge0" "[becausex inRthereforeDiscge0]` `implies(3y-1)(y-3)le0` `1/3leyle3` `implies1/2le(x^(2)-x+1)/(x^(2)+x+1)le3"for all"x inR.` We have, `(sec^(2)theta+tantheta)/(sec^(2)theta-tantheta)=(tan^(2)theta+tantheta-1)/(tan^(2)theta-tantheta+1)` Using statement-2, we have `1/3le (tan^(2)theta+tantheta+1)/(tan^(2)theta-tantheta+1)le3"for all"theta(ne(2n+1)(pi)/(2)),n inZ` `implies1/3le(sec^(2)theta+tantheta)/(sec^(2)theta-tantheta)le3"for all"theta ne2npi+-(pi)/(2)` Hence, both the statements are true and statement-2 is a correct explanation for statement-1. |
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