Firstly, we need to define what a zero of a function is. A zero, also known as a root, of a function is a value of x for which the function evaluates to zero. In simpler terms, a zero is a point where the function crosses the x-axis.
One of the most basic methods for finding the zeros of a function is to set the function equal to zero and solve for x. For example, let us consider the function f(x) = x^2 – 4x + 3. To find the zeros of this function, we set it equal to zero as follows:
x^2 – 4x + 3 = 0
We can then solve for x using the quadratic formula:
x = (-b ± √(b^2 – 4ac)) / 2a
where a, b and c are the coefficients of the quadratic equation (ax^2 + bx + c = 0). In our example, a = 1, b = -4 and c = 3. Substituting these values into the quadratic formula, we get:
x = (4 ± √(16 – 12)) / 2
x = (4 ± √4) / 2
x = 2 ± 1
Therefore, the zeros of f(x) are x = 1 and x = 3.
Another method used to find the zeros of a function is to graph the function and look for the points where it crosses the x-axis. This method is particularly useful for functions that are difficult to solve algebraically. For example, let us consider the function g(x) = x^3 – 6x^2 + 11x – 6. We can graph this function using a calculator or graphing software and observe the points where the function crosses the x-axis:
From the graph, we can see that the zeros of g(x) are x = 1, x = 2 and x = 3.
A third method used to find the zeros of a function is to use synthetic division. Synthetic division is a simplified method for dividing polynomials by a linear factor. It can be used to find the zeros of a polynomial function by testing potential zeros. For example, let us consider the function h(x) = x^3 – 3x^2 – 4x + 12. We can use synthetic division to test whether x = 2 is a zero of h(x):
The remainder is zero, which means that x = 2 is a zero of h(x). We can then use synthetic division again to factor h(x) into a quadratic equation and solve for the remaining zeros:
(2x^2 – 7x – 6)(x – 2) = 0
x = 2, x = 1 and x = -0.5
Therefore, the zeros of h(x) are x = 2, x = 1 and x = -0.5.
In conclusion, finding the zeros of a function involves setting the function equal to zero and solving for x, graphing the function to observe the points where it crosses the x-axis, or using synthetic division to test potential zeros. Each method has its advantages and disadvantages and may be more appropriate for certain types of functions. It is important to note that not all functions have real zeros and some may have multiple zeros. Nonetheless, by utilizing these methods, we can accurately determine the zeros of a function and gain a deeper understanding of its behavior.