已知tanα=-4/3,求2sin^2α+sinαcosα-3cos^2α
<p>问题：已知tanα=-4/3,求2sin^2α+sinαcosα-3cos^2α<p>答案：↓↓↓<p class="nav-title mt10" style="border-top:1px solid #ccc;padding-top: 10px;">何亚农的回答：<div class="content-b">网友采纳 2sin^2α+sinαcosα-3cos^2α =（2sin^2α+sinαcosα-3cos^2α）/(sin^2α+cos^2α) =(2tan^2α+tanα-3)/(tan^2α+1) =-7/25
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