已知,函数f(x)=2sin(2x+π⼀6)+1求它在[0,π]上的单调递增。求大神

2025-02-27 23:24:19
推荐回答(2个)
回答1:

t∈[π/6,2π+π/6]是t的取值范围
而t∈[π/6,π/2]或t∈[3π/2,2π+π/6]
是函数的单调增区间
∵sinα的单调递增区间为[-π/2+2kπ,π/2+2kπ]
∴k取0时,为[-π/2,π/2]得出t∈[π/6,π/2]
k取1时,为[3π/2,5π/2]得出t∈[3π/2,2π+π/6]
∴可得出t∈[π/6,π/2]或t∈[3π/2,2π+π/6]

回答2:

只帮你理解答案,不从解题的角度,你先不要管X,只考虑t,f(t)=2sin(t)+1的单调递增区间为t∈[π/6,π/2]或t∈[3π/2,2π+π/6],这个好理解吧?然后在考虑t=2x+π/6,t∈[π/6,π/2]或t∈[3π/2,2π+π/6]时,x∈[?]就行了