You can perform multiple summations or products. The summation and the product operators have optional placeholders. The operation of these operators depends on which placeholders are filled.
Local Range Variable Definition
When you use all three placeholders for summation or products, you are defining a local range variable that is valid only within the operand.
• The local range variable has no effect on, nor is influenced by, variable definitions outside the operand. For example, you can define the variable j to be 3 meters:
You can then define the local range variable j inside a summation:
When you evaluate j after the summation, you get the following result:
• When you type an equal sign in the bottom placeholder, it is the local variable definition operator and not the evaluation operator.
