Logical Equivalence Checker

This calculator builds the full truth table for two propositional-logic expressions and reports whether they agree on every row. Expression 1 and Expression 2 are each a single operator code — 1 for AND, 2 for OR, 3 for XOR, 4 for IMPLIES, 5 for NAND (evalOp's switch statement, lines 11-18) — and Number of Variables (2 to 4) sets how many rows the table has: rowCount = 2^variableCount (line 8). For more than two variables, evalRow does not evaluate a genuine n-ary version of the chosen operator; it folds the operator pairwise, left to right, across the bits (lines 21-31) — result starts as bits[0], then repeatedly combines with the next bit. That distinction only matters for operators that aren't associative: AND, OR, and XOR give the same answer whichever way you fold them, but IMPLIES and NAND do not, so a three- or four-variable IMPLIES or NAND comparison here reflects that specific left-to-right fold, not a single canonical multi-variable definition — there isn't one.

Matching Rows counts how many of the rowCount truth-table rows produce identical outputs for both expressions, and the two are only reported Equivalent when every row matches. Expression 1 and Number of Variables both default to values that genuinely round back to themselves under a ±10% nudge (Math.round(1.1) and Math.round(0.9) are both 1; Math.round(2.2) and Math.round(1.8) are both 2), so a proportional sensitivity check reads no effect from either. Expression 2 is different: its default of 5 only rounds back to itself on the −10% side (4.5 → 5, still NAND); the +10% side computes Math.round(5.5) = 6, which is outside the calculator's declared 1-5 range and falls through evalOp's switch statement to its default: case (line 17) — coded identically to case 1 (AND) — silently aliasing NAND to AND rather than exercising a genuine sixth operator. A genuinely different, in-range code, like switching Expression 2 from NAND to OR, absolutely changes the result.