Verbose Calculator

With this app you can define variables, functions and write complex math expressions.
There's a handy backlog and you can backtrack, you won't get lost in your calculations.
Constants
E - Returns Euler's number
LN2 - Returns the natural logarithm of 2 (approx. 0.693)
LN10 - Returns the natural logarithm of 10 (approx. 2.302)
LOG2E - Returns the base-2 logarithm of E (approx. 1.442)
LOG10E - Returns the base-10 logarithm of E (approx. 0.434)
PI - Returns PI (approx. 3.14)
SQRT1 -_2 Returns the square root of 1/2 (approx. 0.707)
SQRT2 - Returns the square root of 2 (approx. 1.414)
Functions
abs(x) - Returns the absolute value of x
acos(x) - Returns the arccosine of x, in radians
asin(x) - Returns the arcsine of x, in radians
atan(x) - Returns the arctangent of x as a numeric value between -PI/2 and PI/2 radians
atan2(y,x) - Returns the arctangent of the quotient of its arguments
ceil(x) - Returns x, rounded upwards to the nearest integer
cos(x) - Returns the cosine of x (x is in radians)
exp(x) - Returns the value of pow(E,x)
floor(x) - Returns x, rounded downwards to the nearest integer
log(x) - Returns the natural logarithm (base E) of x
max(x,y,z,…,n) - Returns the number with the highest value
min(x,y,z,…,n) - Returns the number with the lowest value
pow(x,y) - Returns the value of x to the power of y
fact(x) - Returns the factorial of x
random() - Returns a random number between 0 and 1
round(x) - Rounds x to the nearest integer
sin(x) - Returns the sine of x (x is in radians)
sqrt(x) - Returns the square root of x
tan(x) - Returns the tangent of an angle