Chapter 14.1, Problem 2E

The temperature-humidity index I (or humidex, for short) is the perceived air temperature when the actual temperature is T and the relative humidity is h, so we can write $I=f\left(T,h\right)$. The following table of values of I is an excerpt from a table compiled by the National Oceanic & Atmospheric Administration.

Table 3 Apparent temperature as a function of temperature and humidity

Relative humidity (%)
Actual temperature (°F)	h T	20	30	40	50	60	70
	80	77	78	79	81	82	83
	85	82	84	86	88	90	93
	90	87	90	93	96	100	106
	95	93	96	101	107	114	124
	100	99	104	110	120	132	144

(a) What is the value of $f\left(95,70\right)$? What is its meaning?

(b) For what value of h is $f\left(90,h\right)=100$?

(c) For what value of T is $f\left(T,50\right)=88$?

(d) What are the meanings of the functions $I=f\left(80,h\right)$ and $I=f\left(100,h\right)$? Compare the behavior of these two functions of h.