Where is Point B on a Sinusoidal Wave?

[magisbladius]

Homework Statement

For a sinusoidal wave:

At a certain instant, let point A be at the origin and point B be the first point along the x-axis where the wave is 60.0° out of phase with point A. What is the coordinate of point B?

y = (15.0 cm) cos(0.157x - 50.3t)

Homework Equations

The Attempt at a Solution

x(at point B) = theta + 0 = 60.0° = pi/3 rad = ~1.05 m.
y(at point B) = (0.150 m) cos(0.157[1.047 m] - 50.3[0]) = 0.148 m

(x, y) = (1.05, 0.148) m

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I don't understand what the question is asking for. I am handing this in, online, and it checks the answers (I have 3 tries left).

 

[magisbladius]

I found the answer.