The restart command clears Maple's memory of previous assignments.The symbol "cf" is a name, or variable.The assignment operator is "colon equal" and it is used to assign to the variable cf the value computed to the right.The number cf is then the conversion factor for going from degrees to radians. Maple works in radians.Replacing the colon at the end of the line enables you to see the result of the executed command.cf:= 2.0*Pi/360;The name "phasor" is the name of a function that the author is defining. Note the assignment operator that follows the name.The function phasor will have two arguments, namely, x and y.The arrow, made with a minus sign and a greater-than sign, represents a mapping, the mathematician's view of what a function does. It maps from one set (the domain) to another (the range).The rule for the function is Maple's built-in polar command. This command takes two arguments, here represented by the letters x and y. The first argument, x, is the magnitude of a complex number. The second argument is the "angle" for the complex number. Here, it has to be y*cf because y will be given in degrees, but the polar command requires the angle to be in radians. This then represents the complex number in as close to "phasor form" as Maple can manage.phasor:= (x,y)->polar( x, y*cf );sol is a new name, to which is assigned the result of the calculation with phasors that was suggested. Note that the calculation is one phasor divided by the sum of two others. Essentially, one complex number is divided by the sum of two others, where the complex numbers are expressed as "phasors."The evalc is another built-in Maple command designed to put complex expressions into rectangular (a + b i) form, where the imaginary unit LUklbXJvd0c2Iy9JK21vZHVsZW5hbWVHNiJJLFR5cGVzZXR0aW5nR0koX3N5c2xpYkdGJzYkLUkobWZlbmNlZEdGJDYkLUYjNiQtSSZtc3FydEdGJDYjLUYjNiUtSSNtb0dGJDYtUSomdW1pbnVzMDtGJy8lLG1hdGh2YXJpYW50R1Enbm9ybWFsRicvJSZmZW5jZUdRJmZhbHNlRicvJSpzZXBhcmF0b3JHRj4vJSlzdHJldGNoeUdGPi8lKnN5bW1ldHJpY0dGPi8lKGxhcmdlb3BHRj4vJS5tb3ZhYmxlbGltaXRzR0Y+LyUnYWNjZW50R0Y+LyUnbHNwYWNlR1EsMC4yMjIyMjIyZW1GJy8lJ3JzcGFjZUdGTS1JI21uR0YkNiRRIjFGJ0Y5RjlGOUY5Rjk= in Maple is I. (This can be changed to anything you like, including j, but that is a story for another day.)sol:= evalc( phasor(200,0)/( phasor(100,45)+phasor(100,45) ) );The final line is an "expression sequence" containing two results separated by a comma. The first result is the magnitude of the complex number stored in "sol." It is obtained by applying the built-in "abs" command that actually stands for "absolute value." The second member of the sequence is the angle of the rectangular complex number "sol." It is obtained by the built-in "argument" command. But this angle will be in radians. The final division by cf converts radian measure to degrees.abs(sol), argument(sol)/cf;JSFH