# page 69 EXAMPLE 6
reset()
def verify(y1, y2):
    return diff(diff(y1)) + y1 == 0 and diff(diff(y2)) + y2 == 0
def solve(y1, y2):
    return diff(y1/y2) == 0
print verify(cos(x), sin(x))
if solve(cos(x), sin(x)):
    print 'const'
else:
    print 'not a const'