Evaluate: limx→π/6 [(2sin2 x + sinx - 1) / (2sin2 x - 3sin x + 1)]
2sin2 x + sinx - 1 = (2sin x - 1)(sinx + 1)
2sin2 x - 3sin x + 1 = (2sin x - 1)(sinx - 1)
∴ limx→π/6 [(2sin2 x + sinx - 1) / (2sin2 x - 3 sinx + 1)] = limx→π/6 [((2sinx - 1)(sinx + 1) ) / ( (2sinx - 1)(sinx - 1) )]
= limx→π/6 [(sinx + 1) / (sinx - 1) ] (since 2sinx - 1 ≠ 0)
= (1 + sin(π/6)) / (sin(π/6) - 1) = -3