Evaluate function
Substitute a value into a function and simplify. Find f(a) for any expression.
f(x) =
Evaluate at x =
How to evaluate a function
Replace every x with the given value and simplify.
f(x) = x²+3x−5, find f(2): f(2) = 2²+3(2)−5 = 4+6−5 = 5.
Function notation
f(x) names the function. f(2) means "evaluate f at x = 2". The input is 2, the output is f(2).
Evaluating at special values
f(0) gives the y-intercept. f(−x) helps determine even/odd. f(x+h) is used for the difference quotient in calculus.
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