Questions regarding calculators such as the TI-83 (Plus), HP 50g, and other calculator models.

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25
votes
4answers
7k views

Calculator algorithms

Does there exist a good reference on the algorithms used by calculators, especially on the trigonometric and transcendental functions? I would still like to know how Casio generates its random ...
23
votes
6answers
2k views

Why does my calculator show $2^{-329} = 0?$

On my calculator, I usually get a $0$ when I divide something by $2$, a lot of times if that makes sense, but I was just wondering why does $2^{-329} = 0?$
20
votes
7answers
1k views

“Why do I always get 1 when I keep hitting the square root button on my calculator?”

I asked myself this question when I was a young boy playing around with the calculator. Today, I think I know the answer, but I'm not sure whether I'd be able to explain it to a child or layman ...
16
votes
3answers
658 views

Why would a calculator have base 5?

I have a calculator that I found recently that has a base 5 option. It has options labelled HEX, BIN, DEC, OCT, and PEN. My son set it on PEN, and no numbers above 4 worked anymore. Playing around ...
12
votes
9answers
5k views

How to calculate $e^x$ with a standard calculator

Is there a simple method for calculating the $e^x$ ($x\in\mathbb{R}$) with a basic add/subtract/multiply/divide calculator that converges in reasonable time, preferably without having to memorize ...
9
votes
2answers
242 views

How do I find, algorithmically, which parts of a given function are interesting to graph?

I'm building a program that does 2D graphing, and was wondering: How can I determine the default zoom level and x/y extents to display on screen, in such a way as to maximise the 'interesting' parts ...
6
votes
3answers
647 views

Base-2 exponentiation bug on Citizen SR-270X for $2^{255}$?

According to my calculator, $2^{255} = 0.5$. Also, for the range $2^x, x\in[254.5, 255.5)$ the result spans $[0.3535533906, 0.7071067812]$. Outside of that, the answers seem correct. Curiosly, ...
5
votes
3answers
548 views

What is the definition of $2.5!$? (2.5 factorial)

I was messing around with my TI-84 Plus Silver Edition calculator and discovered that it will actually give me values when taking the factorial of any number $n/2$ where $n$ is any integer greater ...
4
votes
4answers
397 views

A question about calculators (are $\sin^2 49^{\circ}$ and $\cos^2 49^{\circ}$ irrational?)

Are $(\sin 49^{\circ})^2$ and $(\cos 49^{\circ})^2$ irrational numbers? When you enter, $(\sin 49^{\circ})^2$ in a calculator, it shows a long number (and if it is irrational, then clearly the ...
4
votes
6answers
840 views

How can I find the value of $\ln( |x|)$ without using the calculator?

I want to know if there is a way to find for example $\ln(2)$, without using the calculator ? Thanks
4
votes
5answers
151 views

Calculate ln(x) using 8-digit calculator

I have a bit of a unique problem. Well, maybe not a problem because I'm really just curious about it, but... I have a simple 8 digit calculator. It has +, -, x, /, and a constant operation function. ...
4
votes
1answer
364 views

What exactly do the sin, cos, tan buttons do on a calculator?

I understand they mean sine, cosine, tangent, but what exactly is the calculator doing when I enter an angle and press those buttons? Edit: To help others better understand my question, my question ...
3
votes
7answers
774 views

Why do I disagree with my calculator?

I followed the order of opperations but my answer disagrees with my calulator's. Problem: $331.91 - 1.03 - 19.90 + 150.00$ Calculator answer: $460.98$ My answer: $162.98$ Why the ...
3
votes
2answers
3k views

How do you plot $x = y^2 - 6$ on a graphing calculator?

I have a graphing calculator app (Graphing Calculator+) that only allows me to enter $x$ as a variable, but I need to graph $x = y^2 - 6$. I haven't used a graphing calculator in awhile. Is this ...
3
votes
4answers
11k views

TI-83 Plus: Is it possible to find the eigenvalues on this calculator?

I searched the Internet and can't seem to find a source on how to find the eigenvalues on a TI-83 Plus calculator. Can anyone give me a hand?
3
votes
5answers
1k views

What type of input does trigonometric functions take in

I see in my Book that 45 deg is equivalent of π/4 . Ι also do the conversion if I simply convert degrees into radians like this 45* π/180 = π/4 radians and ...
3
votes
2answers
84 views

Calculator question involving $\log_2$?

I have a question, I have a calculator that does $\log$ but I think it does it it in a base ten format for example $\log_{10}(100)=2$ I am wondering how I can solve $\log$ using a base of 2 for ...
3
votes
4answers
544 views

Weird stuff happening with complex numbers on a ti-84

So, I'm trying to do some calculations for my Electrical engineering homework. This requires a bit of algebra with complex numbers. I have been finding that some of the calculations that my calculator ...
3
votes
1answer
97 views

Getting the Total value from the Nett

I can't figure out this formula; I need some help to write it out for a php script. I have a value of $\$80$. $\$80$ is the profit from a total sale of $\$100$; $ 20\%$ is the percentage ...
3
votes
1answer
50 views

How to get 2 using a standard scientific calculator without pressing the number buttons 0 to 9 and the buttons $+-\times\div$?

I was challenged by a friend to get a number 2 by using a standard scientific calculator but without pressing the number buttons 0 to 9 and the buttons $+-\times\div$. I could get 1 from $\ln e=1$. ...
3
votes
1answer
121 views

Math for Future Value of Growing Annuity

Am I working this out correctly? I need to verify that my code is correct... $$1000 \cdot \left(\frac{(1 + 0.1 / 12)^{40 * 12} - (1 + 0.06 / 12)^{40 * 12}}{(0.1 / 12) - (0.06 / 12)}\right)$$ ...
3
votes
1answer
65 views

Texas TI-alternatives

I've been using a Texas TI graphing calculator at school and am wondering if there are programs for the PC that function similarly (with similar features) as those calculators. I don't need an ...
3
votes
0answers
191 views

How does my $10\times10$ abacus work?

How does this $10\times10$ abacus work? More specific: Counting: is it common to count from 1 to 100, or from 1 to 9.999.999? How does addition work? How does multiplication work? Are there any ...
2
votes
1answer
251 views

Negative × Negative = Positive… right?

The wife and I were doing homework together, and we noticed something really strange when charting quadratics with a TI-series graphing calculator: ...
2
votes
4answers
9k views

Calculate remainder on Casio fx-991 ES Calculator

Is it possible or not to calculate remainder through use of Casio fx-991 ES Calculator. If possible then how for example :- I have to calculate remainder of ...
2
votes
1answer
4k views

Calculating the percentage of the difference between two values

If I have the following two different values for x: x = 0.022 x = 0.020 And, if I want to calculate the percentage of the difference (change) in x, will it be? ---> 0.022 - 0.020 = 0.002 ---> ...
2
votes
2answers
183 views

In my calculator why does $\sqrt4 -2=-8.1648465955514287168521180122928e-39?$

I have tried this on my Windows 7 calculator with $\sqrt9 -3 $ it too gives some weird answer- ie$1.1546388020691628168216106791278e-37$. And so for any $n$(positive) $\sqrt n^2-n= wierd_ .answer$ Why ...
2
votes
2answers
3k views

is there a CIS button on graphic calculators (Casio/TI)

Is there a cis (CosX + iSinX) Button in CASIO graphic calculators ? if so where its ? if no is there any turn around for it ? PS. I got a CASIO fx-9860G Thanks
2
votes
1answer
224 views

How can I see alternative trigonometry solutions on a calculator?

When doing inverse trigonometric equations on a calculator, only the lowest positive solution is shown. How can I see alternative solutions (specifically for a Casio FX85ES)? Current behaviour: ...
2
votes
2answers
137 views

Simplfy a complex matrix into a real one

I encounter systems of linear complex equations (At most 3 equations) in my circuit analysis course. The calculator I am using is Casio fx-991ES and it only accepts real elements when in matrix or ...
2
votes
3answers
706 views

How to determine end behavior with my TI-83

So, I need to determine the end behavior of $P$ for this equation: $$P(x) = −x^5 + 3x^2 + x.$$ If possible, how is this done?
2
votes
0answers
187 views

Solving $x$ for $y = x^x$ using a normal scientific calculator (no native Lambert W function)?

Solving $x$ for $y = x^x$ using Lambert W function is clear enough thanks to this handy answer, but as I'm using the solution in a network support document I need it in a form that can be solved on a ...
1
vote
9answers
1k views

Computing a very large number

I've been making a program that can delay for any number of nanoseconds 0-65534 to any power 0-65534. That is to say, the shortest possible delay is 0^0 nanoseconds (1) and the longest possible delay ...
1
vote
3answers
2k views

How can I evaluate an expression like $\sin(3\pi/2)$ on a calculator and get an answer in terms of $\pi$?

I have an expression like this that I need to evaluate: $$16\sin(2\pi/3)$$ According to my book the answer is $8\sqrt{3}$. However, when I'm using my calculator to get this I get an answer like ...
1
vote
2answers
227 views

How can I generate a random number on my ti-84 without the rand function

Is there an equation that is possible where I enter a seed, and it will give me the number from the seed. I want it to give me the same results as the rand function would give with the seed as 0. I ...
1
vote
2answers
125 views

In a Calculator, Which Button Should be Bigger: $\sinh()$ or $\rm asin()$?

I am making a calculator app and would like to know: Which of the following functions would be used more often: $\sin()$ $\sinh()$ $\text{arsin}()$ ($\sin^{-1}$) $\text{arsinh}()$ ($\sinh^{-1}$) ...
1
vote
3answers
51 views

Percentage operation gives different results with two scientific calculator

The operation is: $21.99 + 9.75$$\%$ On the Texas Instruments model TI36X-Pro the answer is: $22.0875$ But when I tried on the Casio FX-991ES Plus the result is: $24.134025$ Which is the correct ...
1
vote
1answer
826 views

Integration from 0 to 0 - why does my calculator say “undefined” in one case, and “0” in another?

I have the following question: Using my calculator, $\displaystyle\int_0^{0} \frac{1}{x}dx$ is "undefined". But when I type $\displaystyle\int_0^{0} - \frac{\ln(1-t)}{t} dt$, the result is 0. What ...
1
vote
1answer
41 views

From $\tan\varphi = -3/2 = -1,5$ to $\varphi\approx 123,69^\circ$

Sorry for this question but what do I have to type into my counter to come from $$\tan \varphi = -1,5 $$ to $\approx 123,69^\circ$ and $\approx 303,69^\circ$? Thanks!
1
vote
2answers
101 views

TI83+. Math-> Solver. Why does it give different solutions?

Not sure if anyone still uses this one.... Recall the keystrokes: Math 0:Solver Up arrow Enter equation Press ENTER You will now be at a prompt displaying the equation, and a line saying x=### ...
1
vote
1answer
302 views

How to calculate Mortgage calculation

I have this formula for Mortgage calculation and now i want loan amount value using with same formula. ...
1
vote
1answer
3k views

Checking for symmetry in a graph on the TI-84 Plus

I was using the TI-84 Plus calculator to check for Y-Axis symmetry in the graph of "cos(2X+1)" and as I had to do it fast (I was in the middle of a test), I quickly noted that it was symmetrical. I ...
1
vote
2answers
468 views

Numbers too large for my calculator, probability. Old calculator or should it be done another way?

It's basic binomial probability, the problem is that the numbers are to large for my calculator. Is this the point of the task, to force me to use another method? It doesn't seem lightly, because n ...
1
vote
1answer
438 views

Ti-83 Probability of events occurring

First time here, more frequent over at StackOverflow. So not sure if calculator questions are accepted here, but I'll ask. Is there a quick way to solve problems like this in the ti-83: 82% shot ...
1
vote
2answers
214 views

calculate x using regression equation

I calculated the cubic regression for a set of numbers following the instructions on this site: http://epsstore.ti.com/OA_HTML/csksxvm.jsp?nSetId=71235 I am wondering how do I evaluate using the ...
1
vote
2answers
120 views

Weird computation error when using fnInt (numerical integral) on TI-84 Plus

Today in Calculus class I was bored so I decided to try and approximate $\pi$ by evaluating $ \left( \displaystyle \int_{-a}^a e^{-x^2} dx \right)^2$ on my calculator for larger and larger values of ...
1
vote
1answer
49 views

Graph of $(e^x-1)/x$ as x->0

This question may be as much computer science as math, as I don't believe the reason is mathematical; however an odd thing a classmate of mine pointed out: if you look at a graph of the function in ...
1
vote
1answer
530 views

Calculator for real and complex parts of a polynomial.

Does anyone know of a nice calculator for calculating the real and complex parts of a complex polynomial. Say, for example, I want to write the polynomial $p(z)=z^3+2z^2+1$ as a function ...
1
vote
1answer
136 views

Why does calculator say that $\sqrt{4} = 2$? [duplicate]

Possible Duplicate: Square roots — positive and negative I know that the square roots of four are 2 because $2^2=4$ and $-2$ because $(-2)^2=4$ Are there any conventions in ...
1
vote
2answers
2k views

Gr. 11 Functions - Limiting domain and range on a graphing calculator

I'm trying to do a homework assignment on my graphing calculator app for my ipad (Quick graph+). (Edit by Willie: The images are originally posted here http://imgur.com/a/XRj4g I've included them ...