| − | A '''function''' "''f''" is a fixed method for calculating a unique output "''f(x)''" for every given input 'x'. For example, the [[polynomial]] function <math>f(x) = x^2</math> takes numbers as inputs, and outputs their squares. So in this case, if 1 is input, 1 is output, whilst if 2 is input, 4 is output. | + | A '''function''' "''f''" is a fixed method for calculating a unique output "''f(x)''" for every given input "''x''". For example, the [[polynomial]] function <math>f(x) = x^2</math> takes numbers as inputs, and outputs their squares. So in this case, if 1 is input, 1 is output, whilst if 2 is input, 4 is output. |
| − | A function is typically written with a formula for the output, in terms of the input. For example, in the case of f above, the formula is <math>f(x) = x^2</math>. When we want to input a particular value, we insert it in the place of x. So <math>f(1) = 1^2 = 1*1 = 1</math>. | + | A function is typically written with a formula for the output, in terms of the input. For example, in the case of f above, the formula is <math>f(x) = x^2</math>. When we want to input a particular value, we insert it in the place of x. So <math>f(3) = 3^2 = 3*3 = 9</math>. |