y=sinx+cos2x
=sinx+1-2sin²x
=-2sin²+sinx+1
=-2【sin²-2sinx×1/4+(1/4)²-(1/4)²】+1
=-2【(sinx-1/4)²-1/16】+1
=-2(sinx-1/4)²+1/8+1
=-2(sinx-1/4)²+9/8
≤9/8
所以最大值为9/8,此时sinx=1/4
猜你喜欢
- 1英语翻译
- 2函数图象平移
- 3Private Sub Command1_Click() For i=1 To 4 x=4 For j =1 To 3 x=3 For k=1 To 2 x=x+6 Next k Nex
- 4王老师到体育用品商店为学校买球,他计算了一下,买5个足球和3个篮球要付244元,而买4个足球和6个篮球要付278元.
- 5I hope you feel better soon 中better是good还是well的比较级?
- 6english question.please help me solve it.thank you
- 7在数列{an},{bn}中,a1=2,b1=4,……证明:1/(a1+b1)+1/(a2+b2)+…1/(an+bn)<5/12
- 8一个三位小数四舍五入到百分位约是1.87,这个小数最大是多少?最小是多少?
- 9我有一个梦想(书信)
- 10It’s a _____ (please) trip for all of us.