dom11243
幼苗
共回答了18个问题采纳率:88.9% 举报
y=sinx+√3cosx =2((1/2)sinx+(√3/2)cosx) =2sin(x+π/3) 设t=x+π/3 因为2sint单调增区间为(3π/2+2kπ,5π/2+2kπ)(k∈z) 单调减区间为(π/2+2kπ,3π/2+2kπ)(k∈z) 所以2sin(x+π/3)单调增区间为(π/6+2kπ,13π/6+2kπ)(k∈z) 单调减区间为(π/6+2kπ,7π/6+2kπ)(k∈z) 所以y=sinx+√3cosx=2sin(x+π/3)取最大值时x=π/6+2kπ(k∈z),取最小值时x=7π/6+2kπ(k∈z)
1年前
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