cos−1(cos7π6) is equal to a) 7π6 b) 5π6 c) π3 d) π6
cos−1(cos7π6)=cos−1[cos(2π−5π6)] where, 5π6ϵ[0,π] ∴ cos−1(cos7π6)=cos−1[cos(5π6)]=5π6 [∵cos(2π−θ)=cosθ]
Hence, the correct options is (b).
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 :
The polar form of −√32−i2 (where i = √−1) is
If 0≤x≤π2 and 81sin2x+81cos2x=30 then x is equal to