Precalculus is used in various fields like chemistry, biology and economics in the real world. It is used to make mathematical models or calculations for getting an optimal answer.
In chemistry, precalculus is beneficial in estimating functions like radioactive decay and reaction rate. Aspects like death rate and birth rate can be predicted using precalculus in biology.
Precalculus is also beneficial in computing marginal revenue and cost in economics. This allows economists to estimate the maximum amount of profit that can be made in a particular setting. Precalculus can also be applied for harmonic motions like a pendulum's swing and a Ferris wheel that occur in the real world.