3.1 X(eo)=2xnJe-jon where x[n] is a real sequence. Therefore X(e)=Rl∑xnlo/。 ∑xR(-mu)=∑ x[n]cos(on),and xmm)=m∑刈nm∑刈mc-m)=-2 xn] sin(oon) Since cos(on)and sin(on)are, respectively, even and odd functions of o, Xre(eJo) is an even function of o
Ⅱ. Listening skills W: How much money is the rent for an apartment in this neighborhood M: Your rent should be about a quarter of that Q How much should be the woman's rent be? 2. M: I paid $3, 500 for this digital camera. It was on sale at a 30$ discount w: Its a real bargain
Ⅱ. Listening skills 1. M: Will you love and keep him in sickness and in health, as long as you both shall live? Q: Who is the woman 2. W: Mike, wake upl It is time to go to school. Hurry up or you're going to be late M: Dont worry. I can sleep all day Did you forget today is Martin Luther King's
Ⅱ. Listening skills M: The police gave a few tickets out last week along Highway 15 w: In fact, quite a few tickets were given on that road Q: What does the woman mean? 2. M: Who do you think is the smartest student in the class? w: Mary is second to none Q: What does the woman say about Mary 3. W: What are you so happy about?
Ⅱ. Listening skills Identifying Numbers M: The stadium looks pretty big. How many people does it seat w: It holds around 20,000. They say more than 18,000 Tickets have been sold Q lany tickets are left 2. w: I was planning on signing up for the swimming class. Bit I heard it's full M: Really? Thats strange. There were nine swimming classes last semester, and this semester
