Article: Make sure your hair is dry and smooth. Apply a heat protector product to your hair. Section your hair so the top layer is pulled away from the hair underneath by using hair clips or hair ties. You can actually use a flat iron to lightly curl your hair into beachy waves. Start at the top of a 1 inch (2.5 cm) strand and work the straightener down to the end. While you are pulling the straightener down, twist the straightener around the hair (not the hair around the straightener). Be sure to set your straightener to the right temperature for your hair texture and type. For thin hair, aim for a temperature below 300 °F (149 °C). Normal hair can be ironed at a temperature of 300 to 380 °F (149 to 193 °C). If your hair is thick or coarse, set the straightener to 400 °F (204 °C). Take a large, 2 in (5.1 cm) section of hair. Clamp the curling iron at the bottom of the section and roll it up to the root. Leave it in place for 10 seconds then release. The smaller the section and the longer you leave in the curling iron, the tighter the curls will be. If you are trying to achieve surfer waves, use large sections of hair and only leave the iron in for 10 seconds or less. Take a curling wand and wrap it around a 1 inch (2.5 cm) section of hair. Make sure the wand is pointed down toward the floor. The larger the wand, the longer you leave the hair around it, and the size of the section of hair, will determine how tight the curls are. Curling wands work great for long or short hair. When you are finished with your hair, run your fingers through any sections that are too curly. You can break up the curls so they look more like beach waves instead of tight curls. Brushing your hair can cause it to become fluffy or frizzy. When you like how your hair looks, apply hairspray to hold your beach waves in place. Hair spray comes in various strengths. The finer and flatter your hair is naturally, the stronger hold of hairspray you should use.
Question: What is a summary of what this article is about?
Prepare your hair. Use a flat iron for loose and smooth waves. Use a barrel iron for loose curls. Use a curling wand for light waves. Run your fingers through your hair. Apply hairspray to set your style.

In mathematics, a function is a mathematical relationship between numbers, so that you enter one number and another number is the result. Functions can generally be graphed. They may represents straight lines, parabolas, or random-looking curves that have no easy definition. Some sample functions are:   y(x)=3x+4{\displaystyle y(x)=3x+4} (the function of a straight line)  y(x)=sin(x){\displaystyle y(x)=sin(x)} (a function for a waved line)  y(x)=x2{\displaystyle y(x)=x^{2}} (a function for a parabola) Finding the average rate of change of a function means measuring the value of the function at two different points along the x-axis. Select one value of x where you wish to begin measuring, and then determine how far along the axis you wish to advance. Depending on your purposes, you may choose a wider or narrower range of x values to measure. For this exercise, select the first x-value at 0 and the second x-value at 3. Rate of change of the function measures how much the y-values change over the chosen horizontal x-distance. To calculate this change, you need to know the y values at each chosen value of x. For the sample function, y(x)=x2{\displaystyle y(x)=x^{2}}, select the two values x=0 and x=3, for example. The corresponding values of y(x){\displaystyle y(x)}, therefore, are:  y(0)=02=0{\displaystyle y(0)=0^{2}=0} y(3)=32=9{\displaystyle y(3)=3^{2}=9} The rate of change of a function can be written formally as:  A(x)=ΔyΔx=f(x+h)−f(x)h{\displaystyle A(x)={\frac {\Delta y}{\Delta x}}={\frac {f(x+h)-f(x)}{h}}} In this formula, f(x){\displaystyle f(x)} represents the value of the function at the first chosen x-value. f(x+h){\displaystyle f(x+h)} is the value of the function some distance away at a second value of x. The denominator h{\displaystyle h} is the distance between the two measurements.  h{\displaystyle h} can also be represented as Δx{\displaystyle \Delta x}, since it is the distance or change in the chosen x-values. For the chosen function y(x)=x2{\displaystyle y(x)=x^{2}}, you can calculate the average rate of change from 0 to 3 as follows:  A(x)=ΔyΔx=9−03−0=3{\displaystyle A(x)={\frac {\Delta y}{\Delta x}}={\frac {9-0}{3-0}}=3}. For this function, the rate of change is a measure of how much the value of the function changes vertically as you move horizontally along the x-axis. In this case, the parabola y(x)=x2{\displaystyle y(x)=x^{2}} begins at point (0,0) and climbs to point (3,9) over the measured interval. Although the function itself is not a straight line, the average rate of change is measured as the slope of the straight line connecting those two points. This line climbs 3 units for each single unit increase in x. Note that the average rate of change for a function may differ depending on the location that you choose to measure. For the parabola example, the average rate of change is 3 from x=0 to x=3. However, for the same function measured from x=3 to x=6, also a distance of 3 units, the average rate of change becomes 8.33.
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One-sentence summary --
Know your function. Select values of x. Calculate the values of the function. Calculate the average rate of change of the function. Interpret the result.