关于三角函数的小题?

T=36sin((2π/365)*(t-101))+14<-4
sin((2π/365)*(t-101))<-1/2
2kπ-π/6<(2π/365)*(t-101)<2kπ
或2kπ+π/<(2π/365)*(t-101)<2kπ+7π/6
若2kπ-π/6<(2π/365)*(t-101)<2kπ则
2k-1/6<(2/365)*(t-101)<2k
4380k-365<12t-1212<4380k
365k-70-7/12<t<365k+101
因为0<=t<=364
所以k=0，即0<=t<=101
或者k=1，即295<=t<=364
若2kπ+π/<(2π/365)*(t-101)<2kπ+7π/6则
365k+283.5<t<365k+313+11/12
因为0<=t<=364
所以k=0，即284<=t<=313
综合以上得到
0<=t<=101或284<=t<=364
所以一共有[(101-0)/1+1]+[(364-284)/1+1]=183天是小于-4度的

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