Solving Wave Motion: A Water Wave on a Lake

[asaspades]

Homework Statement

A water wave traveling in a straight line on a lake is described by the equation
y(x,t)=(3.75\,\text{cm})\cos(0.450\,\text{cm}^{-1}x+5.40\,\text{s}^{−1}t)
where y is the displacement perpendicular to the undisturbed surface of the lake.

How much time does it take for one complete wave pattern to go past a fisherman in a boat at anchor?

What horizontal distance does the wave crest travel in that time?

Homework Equations

\omega = 2\pi f
k=\frac{2\pi}{\lambda}

The Attempt at a Solution

This is part of an online test we were asked to submit. For the first part I got t=1.16\,\text{s} which was correct. For the second part I got the wavelength as the answer, \lambda = \frac{2\pi}{0.0045} \approx 1396\,\text{m}. However, the online assessment tells me that the correct answer is 0.140\,\text{m}.

Can anyone explain where I went wrong?

(This is also question 15.10 in University Physics with Modern Physics International Edition, 13th Edition, if anyone should happen to have the solution manual to such a thing)

 

[haruspex]

Your error is in converting 0.450cm⁻¹ to m^-1. You've handled it as though converting from cm to m.