# Cheat sheet of the bc calculator

Using an opensource app, Sensi -Shake to open app, my terminal emulator is opened each time I shake my smartphone, there I run the bc command since I like bc more than the smartphone calculator.

In order to use bc as a scientific calculator, just run it as:

`bc -l`

It only works in radians, so you should learn how to convert radians to degrees. You may use a simple rule of three.

Consider that 180 degrees equals to 4*a(1)

## Variables

You can declare a variable straightforwardly:

a=5

Do not confuse with the following expression:

a==5 which is a logical evaluation that may return true or false.

## Scientific notation

I improvised the scientific notation with the following code in bc:

a=0

if (x>10000) {

while (x>=10) {

x=x/10

a=a+1 }

x; a

}

if (x<0.0001) {

while (x<1) {

x=x*10

a=a+1 }

x; -a

}

## The basic

 π 4*a(1) e e(1) nth(y) root: e(l(x)/y) Square root: sqrt(x)

## Transcendental functions

 Natural logarithm l(x) Common logarithm l(x)/l(10)

## Trigonometric functions:

 sin s(x) cos c(x) tan s(x)/c(x) sec 1/c(x) ctg c(x)/s(x) csc 1/s(x)

 arctg a(x) arcctg 2*a(1)-a(x) arccsc a(1/x)

### Arccosine:

if (x== 0) {
90 } else {
a(sqrt(1/(x^2)-1))
}

### Arcsine:

if (x==1) {
90 } else {
a(sqrt(1/(1-(x^2))-1))
}

### Arc secant:

There is not an integrated function for arcsine, so use the following formula:

2*a(1)-arcsin(1/x)

### Factorial function:

In a bash shell run the following and substitute 500 with the desired number:

`seq -s "*" 1 500 | bc`

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