问题
填空题
若cos(π-θ)=
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答案
因为cos（π-θ）=-cosθ=
，3 5
所以cosθ=-
，3 5
所以cos2θ=2cos2θ-1=2×
-1=-9 25
．7 25
故答案为-
．7 25
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若cos(π-θ)=
|
因为cos（π-θ）=-cosθ=
，3 5
所以cosθ=-
，3 5
所以cos2θ=2cos2θ-1=2×
-1=-9 25
．7 25
故答案为-
．7 25
根据对话内容，从对话后的选项中选出能填入空白处的最佳选项，并在答题卡上将该项涂黑。选项中有两项为多余选项。（共5小题；每小题2分，满分10分） W: Bobby, turn that TV off and set the table. Dinner is almost ready. M: OK. I’ll be right down… W: 1 Your father’s plane was delayed, so he won’t be home until after 10:00. M: Aw, man! Why does he always have to travel so much? 2 W: I know. Your sister and I feel the same way, but this is the way it has to be right now. M: 3 W: That’s because I work from home. 4 Your father is gone a lot, but he also makes good money. M: Why doesn’t he work from home? W: 5 If he stayed at home, how would he ever sell anything?
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