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Grade 1010 grade maths

if a is the root of 25cos^x + 5cosx - 12= 0,90

Profile image of Harshit Srivastava
8 Years agoGrade 10
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Profile image of Vivek
8 Years ago
12cos^2x + 5x-12 =0 doesnt have any root. Taking cosx=y and sobing this quadratic we find value of a which is 6/5and -8/5 these values of y are not possible because cosx lies between -1 to 1