<p>arccos(cosx) = 0. x greater than or equal to 0 and less than or equal to 2 pi. then x could equal</p>
<p>a) 0
b) pi/6
c) pi/4
d) pi/3
e) pi/2</p>
<p>a) 0 ; because cos 0 = 1, cos-1(1) = 0</p>
<p>couldn't you also reason that becuase arccos and cos are inverse functions, by definition, f(g(x))=x where f and g are inverse functions, the answer, so x=0?</p>
<p>ya whoops, i didn't realize arc cos is just another term for cos^-1</p>