InterviewSolution
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InterviewSolution
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For `x in (0,pi)` the equation `sinx+2sin2x-sin3x=3` hasA. infinitely many solutionsB. three solutionsC. one solutionD. no solution |
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Answer» Correct Answer - D `sin x +2 sin 2x- sin 3x=3` `= sin x+4 sin x cos x -3 sin x+4 sin^(3) x=3` `rArr sin x [-2+4 cos x+4(1-cos^(2) x)]=3` `rArr sin x [2-(4 cos^(2) x-4 cos x+1)+1]=3` `rArr 3-(2 cos x-1)^(2) = 3 cosec x` Now `R.H.S. ge 3` But `L.H.S. lt 3` Hence, no solution. |
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