If roots of the equation 2x2−4x+2sinθ−1=0 are of opposite sign, then θ belongs to
Solution : 2x2−4x+2sinθ−1=0 coefficient of x2 is positive f(0)<0 2sinθ−1<0 sinθ<12 θ∈(0,π6)∪(5π6,π)
cos−1x{−cos(−13π6)} is equal to
If the product of the roots of equation 2x2 + ax + 4 sin a = 0 is 1, then roots will be imaginary if :
cos−1(cos7π6) is equal to a) 7π6 b) 5π6 c) π3 d) π6