MATHCAD TUTOR

Part 3: Variables

1. Type
   X:3

   You will see
   X:=3

   Note that the := symbol is quite different from the plain = used in calculations. Always use : to obtain := when you are assigning a numerical value to a variable.

2. Type
   Y:2

   The value 3 has been assigned to the variable X and the value 2 to the variable Y. Any calculation below the assignments statements including these variables will automatically substitute 3 for X and 2 for Y.

3. Now type
   2*X+Y=

4. Now type
   A:3

   B:4

   C:1

   B² - 4AC

5. Now move to the right and above where you assigned values to A,B and C and type
   discr=

   (Make sure and use the regular equals sign, not the colon.) You should get an error message. Now drag the block containing discr= to a position below the definition of discr. This time you should get a number.

6. Here’s how MathCad is a like a spread sheet. Move the cursor back up to where A is assigned the value 3 and change the value to 5. Notice that the value calculated for discr has changed!