sin﹙﹣7/54π﹚与sin﹙﹣8/63π﹚比大小,

问题描述:

sin﹙﹣7/54π﹚与sin﹙﹣8/63π﹚比大小,

sin (54π/7) =sin (7π +5π/7) = -sin(5π/7).sin (63π/8) =sin (7π +7π/8) = -sin(7π/8).因为f(x)=sin x 在(π/2,π)上单调递减,且π/2