HP 15C Instrukcja Użytkownika Pobierz pdf (Strona 184)

184 Section 13: Finding the Roots of an Equation

You have now found the two roots of f(x)

= 0. Note that this quadratic equation

could have been solved algebraically  and

you would have obtained the same roots

that you found using _.

The convenience and power of the _ key become more apparent

when you solve an equation for a root that cannot be determined

algebraically.

Example: Champion ridget hurler Chuck

Fahr throws a ridget with an upward

velocity of 50 meters/second. If the height

of the ridget is expressed as

h = 5000(1  e

t/20

)  200t,

how long does it take for it to reach the

ground again? In this equation, h is the

height in meters and t is the time in seconds.

Solution: The desired solution is the positive value of t at which h = 0.

Use the following subroutine to calculate the height.

Keystrokes

Display

| ¥

000–

´ bA

001–42,21,11

Begin with label.

002– 2

Subroutine assumes t is

loaded in X-and Y-registers.

003– 0

004– 10

1 2 ... 179 180 181 182 183 184 185 186 187 188 189 ... 287 288

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HP 15C Instrukcja Użytkownika Strona 184