求救 一條DSE MATHS MC
http://nakuz.com/home/attachment/201204/4/149892_1333564374harr.jpg內輪佐助 發表於 5-4-2012 02:33 http://www.nakuz.com/bbs/images/common/back.gif
答案係B? 好難計==" practice paper - -
呢條係份卷 難度較高既一題
冇記錯最尾係要你諗
FA/AB 之後用arc sin 搵返個角
至於 FA 就靠 三角形 FDC
入面要既角係靠 平行線 同位角
FCD EBA practice paper - -
呢條係份卷 難度較高既一題
冇記錯最尾係要你諗
FA/AB 之後用arc sin 搵返個角
至於 F ...
天才A 發表於 1-6-2012 22:05 http://www.nakuz.com/bbs/images/common/back.gif
唔多明==" 唔多明=="
愛恨交纏 發表於 2-6-2012 23:24 http://www.nakuz.com/bbs/images/common/back.gif
Let angle ABF=y
angle DCF=angle ABE=34
Let AB=CD=AD=BC=x,
tan34=DF/CD
DF=CDtan34=xtan34
AF=AD-DF=x-xtan34
tany=AF/AB=(x-xtan34)/x=(1-tan34)/1=0.325491483...
y=18.02...
So the angle is 18
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