# Manual

**If you start this program for the first time check out the getting started manual.**

This is the manual for version 1.1. If you need further help or you would like to suggest new features send a mail to info@algeocalc.com

**Calculator:** By default input is evaluated as you type. Pressing OK adds a new input line. Scroll up to see the previous calculations. To switch between radians and degrees, press the menu button in the upper right corner (three dots) then select the "Use radians" checkbox. The `nan`

answer means "not a number". For example `ln(-1)`

returns `nan`

. Press 'Ans' to use the lprevious answer in your next calculation. Note: the last answer must be a number, e.g. the result of a differentiation won't affect the value of 'Ans'.

If you press `^`

or `/`

you will see that Algeo intelligently places the exponent and the denominator. For example pressing `2`

then `^`

makes the cursor jump to the exponent level. Here you can enter the exponent. When you want to jump down to the normal level simply tap to the right of the expression on the blank space. If you don't like this input style then you can turn it off via Menu → Settings → Simple input method.

**Using variables:** There are three variables: `a`

, `b`

and `c`

. You can access them if you swipe the keyboard to the left. The default value for the variables is 0. To set their values use '='. Example:

`a=2+1`

`a^2`

→ `9`

**Using graphs:** You can move the graph by touch. To zoom in and out, use the buttons in the lower right corner. You can trace the function by choosing the Trace icon from the upper icon bar. On every plot line a dot appears. Move your finger across the screen to move the dots. It snaps automatically to intersections and roots of functions. In the upper part of the screen you will see the values of the graphed functions evaluated where the dot is.

**Table of values:** You can generate a numeric table of the functions you specified in the Graph menu. Simply press the button Table. The display shows a list with the values of the functions at the given intervals. You can modify the range settings by pressing the "Edit range" icon.

**Solving equations:** The `solve`

function will solve the given expression in `x`

. If there is no `=`

sign in the equation then it will be solved for 0. So in the example below it solves the equation `x^2=0`

. It only finds one solution. Examples:

`solve(x^2)`

→ `0`

`solve(sinx=cosx)`

→ `0.785398`

**Differentiation:** You can differentiate with the `diff`

function. Its sole parameter is the expression to differentiate. Examples:

`diff(x^2)`

→ `2*x`

`diff(tg(x))`

→ `cos(x)^(-2)`

**Integration:** Use the `int`

function to calculate the definite integral of a function. The first parameter is the function to integrate, the other two are the endpoints of integration. Examples:

`int(x,0,10)`

→ `50`

`int(sinx,-1,1)`

→ `0`

**Taylor-series:** To calculate the Taylor-series of a function use the `taylor`

function. The first parameter is the function, the second is the point the Taylor-series is centered, and third one is the exponent of the biggest element. Examples:

`taylor(ln(x),1,3) `

→ ` x-1-(x-1)^2/2!+(x-1)^3/3!`

`taylor(sinx,0,4) `

→ `-x^3/3!`

**Combinatorics:** The two combinatorial function, `nPr`

and `nCr`

lets you calculate permutations and combinations. `nPr`

calculates the number of r-permutations of n. It gives the the number of ways you can choose r elements and put them in a row from n elements. `nCr`

calculates the number of r-combinations of a set with n elements. It gives the the number of ways you can choose r elements from n elements. Examples:

`nPr(5,2)`

→ `20`

`nCr(5,3)`

→ `10`

**Other functions:** The functions not explained above are listed in the following table:

Function | Description | Example |
---|---|---|

abs | Absolute value | `abs(-5)` → `5` |

exp | Exponential function | `exp(1)` → `2.7182` |

frac | Fractional part | `frac(1.34)` → `0.34` |

floor | Floor function, the integer part | `floor(1.34)` → `1` |

gcd | Greatest common divisor | `gcd(6,4)` → `2` |

log | 10-based logarithm | `log(100)` → `2` |

mod | Calculating remainder | `mod(5,4)` → `1` |