# Solving algebraic equations with the calculator?

• Mar 19th 2009, 10:33 AM
Kaitosan
Solving algebraic equations with the calculator?
I'm in calculus now and for some reason I've still not learned how to solve algebraic equations with the calculator. I've tried to google it but the results are disappointing. Can anyone prod me in the right direction?

FYI, I use the T1-83 calculator.
• Mar 19th 2009, 11:00 AM
Reckoner
Quote:

Originally Posted by Kaitosan
FYI, I use the T1-83 calculator.

Are you looking for exact solutions? In that case you would need a calculator or software that can do symbolic manipulation (such as the TI-89). These are called computer algebra systems (CAS).

If you just want to approximate the solution of an equation numerically, then there are a couple of ways on the TI-83. First move everything in the equation to one side so that the expression is set equal to zero. Then do one of the following.

Use the Equation Solver: select 0:Solver from the MATH menu. Enter in the expression, and then press ENTER. A list of the variables will appear, and you may enter any known values. If you like, enter a guess for the value of the unknown variable (it will help the calculator solve it faster). If there is a specific range of values you want to consider, edit the bound; otherwise leave the default. Then highlight the variable you want to solve for, press ALPHA, and then press SOLVE (above the ENTER key).

Alternatively, enter your expression in the Y= editor, and graph it. Press 2nd and then CALC, and choose 2:zero. If you have multiple functions graphed, use the up and down arrows to cycle to the one you want. Then use the left and right arrows to set the lower and upper bounds for the search. Finally, make a guess for the zero. The cursor moves to the intercept, and the coordinates are given. The $x$-coordinate is the one you want.

(And by the way, all of this is very easily found in the calculator's manual, which is itself easily found with Google)
• Mar 19th 2009, 11:04 AM
skeeter
Quote:

Originally Posted by Kaitosan
I'm in calculus now and for some reason I've still not learned how to solve algebraic equations with the calculator. I've tried to google it but the results are disappointing. Can anyone prod me in the right direction?

FYI, I use the T1-83 calculator.

say you want to solve an equation for a single variable ...

expression 1 = expression 2

imho, the best way to solve an equation with the calculator is to graph

Y1 = expression 1 - expression 2

and calculate the x-intercepts (zeros). just make sure that y-min is negative and y-max is positive so that you may see the x-axis.
• Mar 19th 2009, 12:15 PM
Kaitosan
Hey guys, thanks for the help! I knew about the zero method but for some reason it didn't come to my mind lol. But I learned about the solving function through the MATH button; it's new information for me. Thanks.
• Mar 20th 2009, 02:25 AM
earboth
Quote:

Originally Posted by Kaitosan
I'm in calculus now and for some reason I've still not learned how to solve algebraic equations with the calculator. I've tried to google it but the results are disappointing. Can anyone prod me in the right direction?

FYI, I use the T1-83 calculator.

You find an equation solver at:

MATH --> MATH --> 0:SOLVER

The calculator uses a build-in iteration program thus you only get an approximate solution.

Have a look here: http://www.mathhelpforum.com/math-he...-equation.html