# 3 – Functions

• What if you could predict a thunderstorm? Or a tornado? Or a tsunami?
• What if you could use this information to warn people ahead of time about a possible disaster and save their lives?
• Maybe you could estimate when an earthquake might happen…or a mudslide.
• Or perhaps you could determine the area where a meteor might fall to earth.
• Understanding functions is key to making these and other important predictions. A function is the relationship between a set of inputs and its set of possible outputs.
• Imagine you’re a meteorologist developing an equation to estimate the temperature of the air at a certain location and a certain time, based on how high you are above the ocean.
• What happens if you choose a lower altitude?
• Or a higher one? How does that change your prediction?
• Whether you want to invest in the stock market, program a computer, or investigate the scene of an accident, functions are helpful tools for understanding and solving problems of all types.
• In this unit you’ll discover the power of functions and how they relate to you and your everyday life.