5
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So the problem is to find all points $(x,y)$ on the real plane such that $f(x,y) = \cos^2(x+t) + 2\sin(x+t)\cos(y) - \frac{(\cos y - 1)^2}{2} - \sin(x) \lt .5$ for all real $t$. I'm not sure where to start with this, I don't think I fully understand the equation... how can the result be in terms of $f(x,y)$ when $t$ is also essentially a variable? shouldn't this be a 3 dimensional plot?

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