这道题怎么做呢？

来源：百度知道 编辑：UC知道 时间：2024/05/26 01:10:26
就是在横线上填什么！谢谢你！

suppose you are on the island with Chuck and Wilson(the volleyball) Chuck often "talks" to Wilson,but he can,t hear what Wilson says, so you have to tell Chuck what Wilson says in lndirect Speech.Read the conversation. Can you guess what Wilson says?Write down what Wilson says,using Direct Speech as in the example

EXPMPLE:
WILSON:Can we talk Chuck?
YOU:Chuck Wilson asks if he can talk with you
Chuck:yes,sure We can talk

CHUCK:I know,i know You are angry with me You think we should wait longer,but we have waited long enough already
YOU:_________________________________
CHUCK:Yes.you are my friend,but I miss the others
WILSON:_______________________________________________________
YOU:______________________________________________________________
CHUCK:We have been here for almost five years.
WILSON:_________________________________________________
YOU:________________

在直角三角形ABC中，角A=90度，斜边上的高AD=5，AB=2AC，求BC的长
解:AB=2AC,所以tanB=1/2,cotB=2,角CAD=角B,于是:
CD/AD=tanB=1/2,CD=5/2,DB/AD=cotB=2,DB=10,BC=CD+DB=12.5.
在直角三角形ABC中，角ACB=90度，CD垂直AB于D，BC=15，cosA=4/5,求 AC,BD,CD及AB的长
解:sinA^2+cosA^2=1,cosA=4/5,所以sinA=3/5,BC=15,于是:
BC/AB=sinA=3/5,AB=5BC/3=25,AC^2+BC^2=AB^2,AC^2=AB^2-BC^2
AC=20.CD/AC=sinA=3/5,CD=3AC/5=12.
BD^2=BC^2-CD^2,BD=9.若用三角函数,sinA=cosB=3/5,
BD/AB=cosB=3/5,BD=3AB/5=9.总之,学了三角函数后解题方法会更多.