Solution
= Solution
The identity $\sin^3x=(3\sin x-\sin3x)/4$ makes the lower-order cancellation explicit. Expand the two sines through degree seven:
$$
\boxed{\sin^3x=x^3-\frac{x^5}{2}+\frac{13x^7}{120}+O(x^9).}
$$
These are the first three nonzero terms; there is no linear term.