In pre calculus you learn mostly about functions (trigonometric, logarithmic and exponential) along with limits, complex numbers, etc.
Resources
Kutasoftware.com Themathpage.com Mathworksheetscenter.com Openlab.bmcc.cundy.edu - Functions: Functions relate an input with an output. Most of the time it'll be X as the input which influnces Y, the output. An example of this is f(x) = 2x in which Y will be twice as much as the given value of X. - Trigonometric functions: Trigonometric functions are fucntions which relate an angle to the ratios of two side lengths that the angle creates in a triangle. - Logarithmic functions: Logarithmic functions are functions using logs which are the the inverse of exponents. - Exponential functions: Exponential functions are functions which use exponents (multiplying the given number under the exponent by itself the amount of times the exponent says).