B-16 TI-85/TI-86 Graphing Calculators
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To graphically find an x-intercept, i.e., a value of x at
which the graph crosses the horizontal axis, first press
EXIT to return the menu to the bottom of the screen.
TI-85 Press F1 (MATH) F3 (ROOT )
TI-86 Press F1 (MATH) F1 (ROOT )
Both Use to move the trace cursor near the first
x-intercept, and press ENTER .
To find the second x-intercept, press EXIT and the
F-key under ROOT, use to move the trace cursor
near the other x-intercept, and press ENTER .
& 1.3 Constructed Functions
Your calculator can find output values of and graph combinations of functions in the same
way that you do these things for a single function. The only additional information you need
is how to enter constructed functions in the graphing list. Suppose that a function f(x) has
been entered in y1 and a function g(x) has been entered in y2.
¥ Enter y1 + y2 in y3 to obtain the sum function (f+g)(x) = f(x) + g(x).
¥ Enter y1 Ð y2 in y4 to obtain the sum function (fÐg)(x) = f(x) Ðg(x).
¥ Enter y1*y2 in y5 to obtain the product function (f
.
g)(x) = f(x) * g(x).
¥ Enter y1/y2 in y6 to obtain the quotient function (f
¸
g)(x) =
fx
gx
()
()
.
