### Home > CALC > Chapter 1 > Lesson 1.5.1 > Problem 1-202

1-202.

When is the cos(*x*) = to 0?

Logarithms have restrictive domains: *x* cannot be less than or equal to 0. What value(s) of *x* will make *x*² + 1 ≤ 0?

*D* = (−∞, ∞)

*x*² - *x* - 6 ≠ 0

Both the numerator and the denominator have restricted domains. To find the domain of *k*(*x*), all restrictions apply... combine the domains together.