The ∏() Command Command Summary

Multiplies together the evaluations of an expression with one variable taking on a range of values.

Command Syntax

∏(expression, variable, start, end)

• Press 2nd MATH to enter the MATH popup menu.
• Press B to enter the Calculus submenu.
• Press 5 to select ∏(.

This command works on all calculators.

2 bytes

∏() is used to multiply a sequence of numbers. ∏(expression, variable, start, end) will evaluate expression for variable=start, then for variable=start+1, all the way through variable=end, and multiply the results:

``````:∏(f(x),x,1,5)
f(1)*f(2)*f(3)*f(4)*f(5)
:∏(x,x,1,5)
120```
```

In this way, ∏() is no different from taking product() of a sequence generated by seq(). However, ∏() can be used for more abstract calculations — for instance, when start or end is an undefined variable, it will try to find the product in terms of that variable. ∏() can also be used to find the product of an infinite series (just make the value of end infinity — ∞).

``````:∏(x,x,1,n)
n!
:∏(1-1/x,x,2,n)
1/n```
```