Texas Instruments TI-92+, Tip List

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Now you need to transfer that measurement onto the circle. Select F4, 9 (measurement transfer).
Then select the measurement from step 6. Then select the circle. Next select the intersection point
of the circle and the segment. A point will appear on the circle.
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Reflect this point across the perpendicular line. (F5, 4, select the point, then select the
perpendicular line) A new point should appear on the other side of the perpendicular line.
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Hide the perpendicular line and the first point created on the circle. (F7, 1, click on the line, click on
the point)
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Now change the format of the Locus to be nonlinked points. (F8, 9, set Link Locus Points to OFF)
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The last step is to draw the locus. Press F4, A, select the point reflected across the perpendicular
line and then select the intersection point.
The locus will appear after the last step.
infinite sums - why does the TI-92 only compute certain ones?
The TI-92 symbolic math pack can only recognize certain sums. We built in what we thought was most
needed to support the Calculus curriculum.
Memory requirement to open any application on the TI-92?
Geometry requires about 23K bytes of free memory to start a new session. All other applications
require less than 100 bytes to create/open an empty file.
Note: The amount of free memory required to open existing files is dependent on the size of the file.
Maximum number of variables?
If the data types are small enough that free memory does not become an issue, you can store
approximately 800 different variables.
Locked variables don't show up in open dialog box choices - why?
The purpose of locked variables was to keep the variable from changing. All of the editors (Program,
Geometry, Data/Matrix, Text) edit the variable directly in memory (they don't work on a copy of the
variable, but instead the only copy of the variable). So, to edit one of these variable, you must first
unlock it from either the Var-Link dialog box or using the Unlock command.
Limit() returns an answer when you expect undefined - why?
Why does the TI-92 returns 0 for limit(sqt(1-x),x,1) when it should be undefined?
The limit actually does exist from the right side, it is just an imaginary solution not a real one. That is
where the problem arises. Right now, the TI-92 does not filter out answers like this. In fact, an answer
should only be returned if you approach 1 from the left side. From both sides and from the right side it
should not exist. This is simply a limitation of the TI-92 (and some other CAS systems).
In cases like this, it is a good idea to check the problem using two or three different methods.... limit on
home screen, graph the argument, and use the table.
Integration (symbolic) function algorithm
Antiderivatives are determined by substititutions, integration by parts, and partial-fraction expansion,
much as described by J. Moses ("Symbolic Integration: The Stormy Decade", Communications of the
ACM, August 1971, Volume 14, Number 8, pp. 548-559.) Antiderivatives are NOT computed by any
of the Risch-type algorithms.) Definite integrals are determined by subdividing the interval at detected
singularities, then for each interval, computing the difference of the limit of an antiderivative at the
upper and lower integration limits. Except in exact mode, nINT() is used were applicable when
symbolic methods don't succeed.
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