7.已知對(duì)任意平面向量
=(x,y),把
繞其起點(diǎn)沿逆時(shí)針方向旋轉(zhuǎn)θ角得到向量
=(xcosθ-ysinθ,xsinθ+ycosθ),叫做把點(diǎn)B繞點(diǎn)A沿逆時(shí)針方向旋轉(zhuǎn)θ角得到點(diǎn)P.已知平面內(nèi)點(diǎn)A(1,2),點(diǎn)
,把點(diǎn)B繞點(diǎn)A沿順時(shí)針方向旋轉(zhuǎn)
后得到點(diǎn)P,則點(diǎn)P的坐標(biāo)為( ?。?/div>
四、解答題:本題共6小題,共70分,解答應(yīng)寫出文字說明、證明過程或演算步驟
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