Not a one-to-one function; no inverse
Work Step by Step
The function $d(t)$ represents the depth of the tide in terms of the time $t$ over a 24 hours period. The function $d$ is a one-to-one function if every input corresponds to only one output. As the tide oscillates, there are times $t$ for which the depth is the same, so the function is not one-to-one; therefore it doesn't have an inverse.