想一想想一想P6240cm30cmAB,.1:bcmAD 设解40cm30cmxcmbcm.3043xb易得 3043.2xxxby.30020432xxx30432AB40cm30cmxcmbcm:或用公式AB40cm30cmxcmbcm.300442abacy最大值,202时当abxADNbcmxcm,.1:bcmAB 设解.4034xb易得BD40cm30cm 4034.2xxxby.30015342x xx40342:或用公式 BD40cm.300442abacy最大值,152时当abxxcmbcm：由勾股定理得解.1:.242512,xbbcmAB易得设G.24,50cmPHcmMN 242512.2xxxby.3002525122xxx2425122xcmbcmG:或用公式xcmbcmG,252时当abx.300442abacy最大值 做一做做一做.1574.1:xxy由解.4715,xxy得 做一做做一做xx215272 24715222.222xxxxxxyS窗户面积.562251415272x 做一做做一做,07.114152:时当或用公式abx 做一做做一做abacy442最大值.02.456225 议一议议一议作 业作 业P63页习题2.8 第1、2题.结束寄语函数函数y=ax2+bx+c(a0)的应用的应用 想一想想一想 做一做做一做 做一做做一做
