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已知函数f(x)=根号2asin(x-π/4)+a+b1)当a=1时,求函数f(x)的单调递减区间2)当s

题目详情
已知函数f(x)=根号2asin(x-π/4)+a+b
1)当a=1时,求函数f(x)的单调递减区间
2)当s
▼优质解答
答案和解析
(1) sinx的单调递减区间为[2kπ+π/2,2kπ+3π/2]
sin(x-π/4)的单调递减区间为[2kπ+π/2+π/4,2kπ+3π/2+π/4]即[2kπ+3π/4,2kπ+7π/4],(k为任意常数)
于是当a=1时,f(x)=根号2 sin(x-π/4)+1+b的单调递减区间为
[2kπ+3π/4,2kπ+7π/4],(k为任意常数)
(2) 当x∈[0,π]时,则x-π/4∈[-π/4,3π/4],于是sin(x-π/4)∈[-√2 /2,1]
那么当a