不求值比較大小(單調(diào)性求)cos[(-47/10)派]與cos[(-44/9)派]
熱心網(wǎng)友
cos(-47/10*pi)=cos(-2pi-7/10*pi)=cos(-7pi/10)=cos(7pi/10)cos(-44/9*pi)=cos(-2pi-8pi/9)=cos(-8pi/9)=cos(8pi/9)在區(qū)間(0,pi)內(nèi)y=cosx是減函數(shù).又0cos(8pi/9)---cos(-47pi/10cos(-44pi/9)
不求值比較大小(單調(diào)性求)cos[(-47/10)派]與cos[(-44/9)派]
cos(-47/10*pi)=cos(-2pi-7/10*pi)=cos(-7pi/10)=cos(7pi/10)cos(-44/9*pi)=cos(-2pi-8pi/9)=cos(-8pi/9)=cos(8pi/9)在區(qū)間(0,pi)內(nèi)y=cosx是減函數(shù).又0cos(8pi/9)---cos(-47pi/10cos(-44pi/9)