範例14B

 

 

試求二直線L1:2x-y+3=0L2: x+y+1=0的交角

[解法]

<Sol.>
cosq=
          =
          =
         
»0.3162
         
»cos71°34'(見註)
q=71°34'108°26' (補角)
[
]



x
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