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春芽
共回答了17个问题采纳率:100% 举报
LIM(X趋向0)(tanx-x)/x³=LIM(X趋向0)(sec²x-1)/(3x²)=LIM(X趋向0)(1-cos²x)/(3x²cos²x)
=LIM(X趋向0)(sinx/x)²/(3cos²x)=1/3
LIM(X趋向0)x³/(x-sinx)=LIM(X趋向0)3x²/(1-cosx)=LIM(X趋向0)3x²/2 sin²(x/2)
=LIM(X趋向0) 6 [(x/2)/sin(x/2)]²=6
原极限=(1/3)6=2
1年前
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