If for all real values of x, 4x2+164x2−96xsinα+5<132 then α lies in the interval-
128x2+32<64x2−96sinα+5
64x2+96sinα+27<0
Thus x is real.
For real x,
B2−4AC>0
Or
(96sinα)2−4(64×27)>0
Or
sin2α>34
Or
sinα>√32 or sinα<−√32.
Or
αϵ(π3,2π3)∪(4π3,5π3)