Documentation moved.
This entry is now part of the unified function reference. Open the unified page →
Function
src/math/math.ts:1656product
product(expr: Expression, index: Expression, lower: Expression, upper: Expression): ExpressionComputes a finite product:
`product(expr, k, a, b) = Π_{k=a}^{b} expr`. - If bounds are integers and the number of terms ≤
`Settings.MAX_PRODUCT_AND_SUMMATION_ITERATION`, evaluates by multiplying each term. - If
`lower > upper`, returns
`1`(empty product). - If
`expr`does not depend on the index variable, simplifies to
`expr^(b − a + 1)`. - Otherwise returns a symbolic
`product(expr, k, a, b)`node.
Parameters
| Name | Type | Description |
|---|---|---|
expr | Expression | The expression to be multiplied. |
index | Expression | The index variable (must be a plain symbol). |
lower | Expression | The lower bound (integer required for evaluation). |
upper | Expression | The upper bound (integer required for evaluation). |
Returns
Expression — The product result or a symbolic `product` node.
Examples
// Π_{k=1}^{5} k = 120 (same as 5!)
product('k', 'k', 1, 5).text() // "120"