sin(3X-π/6）=sin3π/4=sin7π/4=-√2/2
即3X-π/6=2Kπ+3π/4=2Kπ+7π/4,
3X=2Kπ+11π/12,3X=2Kπ+23π12,所以X=2Kπ/3+11π36,X=2Kπ/3+23π36