If 

$f(x)=\left|\begin{array}{ccc}1 & 1 & x+1 \\ 2 x & x(x-1) & x(x+1) \\ 3 x(x-1) & 2(x-1)(x-2) & x(x+1)(x-1)\end{array}\right|$ 

then what is f(-1) + f(0) + f(1) equal to?

The equation $sin^{-1}x-cos^{-1}x=\frac{\pi}{6}$ has

What is the value of the following?

(sin 24° + cos 66°)(sin 24° - cos 66°)

A chord subtends an angle 120° at the centre of a unit circle. What is the length of the chord?