Function TR2

src/compute-engine/symbolic/fu-transforms.ts:120–139

(expr: Expression)

// ============================================================================

export function TR2(expr: Expression): Expression | undefined {
  const ce = expr.engine;
  const op = expr.operator;
  if (!isFunction(expr)) return undefined;
  const arg = expr.op1;

  if (!arg) return undefined;

  if (op === 'Tan') {
    // tan(x) -> sin(x)/cos(x)
    return ce._fn('Sin', [arg]).div(ce._fn('Cos', [arg]));
  }

  if (op === 'Cot') {
    // cot(x) -> cos(x)/sin(x)
    return ce._fn('Cos', [arg]).div(ce._fn('Sin', [arg]));
  }

  return undefined;
}

/**
 * Apply TR2 to all subexpressions