Function roots

test/compute-engine/solve.test.ts:722–726

(s: string)

  // R28b regression: inverse trig/hyperbolic functions now numericize to
  // complex values off their real domain, so the out-of-domain rejection must
  // happen in the rule guards (it used to fall out of the roots failing to
  // numericize). The guards also used to miss exact ratios bound as
  // `NumericValue` instances (`typeof val === 'number'` was false for the
  // `ExactNumericValue` −2), silently admitting any exact out-of-range ratio.
  test('should return empty for tanh(x) = 2 (no real solution)', () => {
    // tanh(x) can only be in (-1, 1)
    expect(expr('\\tanh(x) = 2').solve('x')).toEqual([]);