Given : \[ \begin{array}{l} f(x)=2 x+1 \\ g(x)=5 \times 2 \\ h(x)=x+3 \end{array} \] 1. \( (f \circ g)(x) \) 2. \( (g=f)(x) \) 3. \( (h \circ g)(x) \) 4. \( (f \circ h)(x) \) Finally, we are almost done with the preview of Functions! Some real life situations can also be represented by functions. Take a closer look at how some events are written as functio is! FUNCTIONS IN REAL-LIFE SITUATIONS 1) Suppose that s ( \( ( \) ) is the top speed (in km per hour) of a runner when the temperature is \( T \) degrees Celsius. Explain what the statements \( s(15)=12 \) and \( s(30) \) \( =10 \) mean. Solution: The first equation means that when the temperature is \( 15^{\circ} \mathrm{C} \), then the top speed of a runner is 12 km per hour. However, when temperature rises to \( 30^{\circ} \mathrm{C} \), the top speed is reduced to 10 km per hour. 2). The velocity \( V \) (in \( \mathrm{m} / \mathrm{s} \) ) of a ball thrown upward \( t \) seconds after the ball was thrown is given by \( V(t)=20-9.8 t \). Calculate \( V(0) \) and \( V(1) \), and explain what these results mean. Solution. \( V(0)=20-9.8(0)=20 \) and \( V(1)=20-9.8(1)=10.2 \). These results indicate that the initial velocity of the ball is \( 20 \mathrm{~m} / \mathrm{s} \). After 1 second, the ball is traveling more slowly, at \( 10.2 \mathrm{~m} / \mathrm{s} \). Do you want to try expressing real life situations as a function of an unknown variable? Answer Activity 6 below.
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\( (f \circ g)(x) \) means we first apply the function g(x) to x, and then apply the function f(x) to the result. So, \( (f \circ g)(x) = f(g(x)) = f(5 \times 2) = f(10) = 2(10) + 1 = 21 \). Show more…
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