Question

已知如图在Rt△ABC中,∠ABC=90º,AB=4,sin∠BAC=3/5,P是边AC上的一点……九上期中考试题

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Answer 1

(1)
设∠BAC=α
sinα=BC/AC=3/5
BC=3/5AC
AB=4
AB^2+BC^2=AC^2
16+9/25AC^2=AC^2
AC^2=25
AC=5
BC=3

(2)
AD∥BC，BC⊥AB
AD⊥AB
DP⊥AC
△ABC∽△ADP
AD/AC=AP/BC
AC=5，BC=3，AP=x
AD=5/3x

△ADE中AD∥BC
BC/AD=BE/AE
BC=3，AE=BE+AB=BE+4，BE=y

3/(5/3x)=y/(y+4)
5/3xy=3y+12
y=36/(5x-9)

(3)
当AD=DC时
AP=1/2AC=5/2
BE=36/(5x5/2-9)
BE=72/7

当AD=AC时
AP=3，AD=AC=5

BE=36/(5x3-9)=6

Answer 2

怎么把题目内容弄的超高压支离破碎的？？