diff ((sin (x)*x**2)/(1+tan (cot (x))))
diff(x**2*sin(x)/(tan(cot(x)) + 1), x)
solve(x**2*sin(x)/(tan(cot(x)) + 1), x)
series(x**2*sin(x)/(tan(cot(x)) + 1), x, 0, 10)
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