A sine function is a mathematical function that describes a smooth, periodic oscillation. It is commonly represented as y = \sin(x) , where x is the angle in radians. The sine function produces values between -1 and 1, making it useful in various applications, including trigonometry, physics, and engineering. The graph of a sine function is a wave-like pattern that repeats every 2\pi radians. This repeating nature is known as periodicity. The sine function is essential for modeling phenomena such as sound waves, light waves, and other oscillatory motions in the natural world.