lwzyhm
幼苗
共回答了21个问题采纳率:81% 举报
limx→0(√2-√(1+cosx))/(sin3x)^2=lim(1-cosx)/[(sin3x)^2(√2+√(1+cosx))]
=lim(1-(1-2sin^2(x/2)))/[(sin3x)^2(√2+√(1+cosx))]
=lim2sin^2(x/2)/[(sin3x)^2(√2+√(1+cosx))]
=lim2sin^2(x/2)*1/4/(x/2)^2/[(sin3x)^2*9/(3x)^2*(√2+√(1+cosx))]
=2*1/4/9/2√2=√2/72
1年前
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