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题型:单选题 题类:常考题 难易度:普通
归纳推理
sin230°+cos260°+sin30°cos60°=;由此可归纳出对任意角度θ都成立的一个等式,并予以证明.
(sin )﹣2+(sin )﹣2= ×1×2;
(sin )﹣2+(sin )﹣2+(sin )﹣2+sin( )﹣2= ×2×3;
(sin )﹣2+(sin )﹣2+(sin )﹣2+…+sin( )﹣2= ×3×4;
(sin )﹣2+(sin )﹣2+(sin )﹣2+…+sin( )﹣2= ×4×5;
…
照此规律,
(sin )﹣2+(sin )﹣2+(sin )﹣2+…+(sin )﹣2={#blank#}1{#/blank#}.
sin230°+cos260°+sin30°cos60°= ;由此可归纳出对任意角度θ都成立的一个等式,并予以证明.
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