Find Domain?

f(x)=^{[2 ]}((cosx-1/2)(6+35x-6x²))

hello richeek..let me add on to u..

see u have approached in right way that each of the functions comprissing f(x) must be positive becaise square root of negative is undefined.....the estimation of quadratic part is done correctly above..however for the cos part....

cos(x) - 0.5 > 0 that means cos(x)>.5...now make graph of cos(x) in the principle value region....we get x>pi/3 and also x>5*pi/3....

now since both the conditions of cos as well as quadratic neeed to be satisfied so take intersection of above two inequalities