```ts
/**
 * A divided by b, where both arguments are finite numbers.
 */
export function safeDivide(a: number, b: number): number {
  if (!Number.isFinite(a) || !Number.isFinite(b)) {
    throw new Error('Both arguments must be finite numbers');
  }
  if (b === 0) {
    throw new Error('The divisor cannot be zero');
  }
  return a / b;
}
```