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The sum of roots of equation 4cos^(3) (Pi + x) – 4cos^(2)(Pi – x) + cos(Pi + x) – 1 = 0 in the interval [0,320] is p Pi. Then p is equal to :- |
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Answer» `4 cos^(3)x + 4cos^(2)x+cosx+1 = 0` `(4cos^(2)x+1)(cosx+1) = 0` `cos x = -1` `x = (2n -+ 1) Pi` `N = 012 ………….49, 50` `x = Pi, 3 Pi, 5Pi …………… 99 Pi , 101 Pi` `S = Pi + 3 Pi + …………+ 101 Pi` `S = 2601 Pi`. |
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