Usage of software: just enter an expression, variables, their values and, finally, press the button ‘=’. The calculated function value will appear in the result field or you will see a window with error description. In order to save function and variables you must press the button 
in the right part of the function text field. There you can choose the function previously saved for repeated calculation.
To draw the graphs, press the button 
in the bottom of the screen. At the same time, note that within this mode you can use only one variable ‘x’ in the function body. Multitouch is supported in this mode.
In the expression you can use ordinary operators, such as ‘+’,’-‘, ‘*’, ‘/’ and also ‘^’ as exponentiation, ‘%’ as residue of division, ‘!’ as factorial. Besides, there are preinstalled functions. Their list is given below. To change the priority of operations, a part of expression can be inserted into parenthesis.
You can use the following constants:
$pi – pi number (3.14159…)
$e – e number (2.71828…)
While entering numbers you can use E notation, for example, 1.3e5 i.e. 130000.
Value of the trigonometric functions depends on the position of the switch:
DEG - degrees
RAD - radians
GRAD - gradians
List of supported functions
Trigonometric functions
sin(x) - sine of x
cos(x) - cosine of x
tg(x) - tangent of x
tan(x) - also tangent of x
ctg(x) - cotanget of x
cot(x) - also cotanget of x
sec(x) - secant of x
cosec(x) - cosecant of x
csc(x) - also cosecant of x
arcsin(x) - arcsine of x
arccos(x) - arccosine of x
arctg(x) - arctangent of x
arctan(x) - also arctangent of x
arcctg(x) - arccotangent of x
arccot(x) - also arccotangent of x
arcsec(x) - arcsecant of x
arccosec(x) - arccosecant of x
arccsc(x) - also arccosecant of x
Hyperbolic function
sinh(x) - hiperbolic sine of x
sh(x) - also hiperbolic sine of x
cosh(x) - hiperbolic cosine of x
ch(x) - also hiperbolic cosine of x
tanh(x) - hiperbolic tangents of x
th(x) - also hiperbolic tangents of x
coth(x) - hiperbolic cotangent of x
cth(x) - also hiperbolic cotangent of x
sech(x) - hiperbolic secant of x
cosech(x) - hiperbolic cosecant of x
csch(x) - also hiperbolic cosecant of x
arsh(x) - inverse hiperbolic sine of x
arch(x) - inverse hiperbolic cosine of x
arth(x) - inverse hiperbolic tangent of x
arcth(x) - inverse hiperbolic cotangent of x
arsch1(x) - inverse hiperbolic secant of x (with plus sign)
arsch2(x) - inverse hiperbolic secant of x (with minus sign)
arcsch(x) - inverse hiperbolic cosecant of x
Other functions
abs(x) - absolute value of x
lg(x) - common logarithm of x
log10(x) - also common logarithm of x
ln(x) - natural logarithm of x
log2(x) - binary logarithm of x
log(b, x) - logarithm of x to base b
exp(x) - exponential function of x
sqrt(x) - square root of x
cbrt(x) - cube root of x
round(x) - rounded value of x
rand(x) - random value from 0 to x
pow(x, y) - x raised to power y, y maybe less then 1, for example, pow(8, 1/3) - cube root of 8
