lim 1-cos4x/2sin^2x+xtan^2x x趋近于0 求极限

lim 1-cos4x/2sin^2x+xtan^2x x趋近于0 求极限
lim 1-cos4x/2sin^2x+xtan^2x x趋近于0 求极限

lim 1-cos4x/2sin^2x+xtan^2x x趋近于0 求极限
因为1-cos4x/2sin^2x+xtan^2x
=1-（1-2sin^2x)/2sin^2x+sin^2x/cos^2x
=2sin^2x/2sin^2x+sin^2x/cos^2x
=2/1+1/cos^2x
所以原式=2/2=1

lim 1-cos4x/2sin^2x+xtan^2x x趋近于0
=lim （1-cos4x）/（2sin^2x+xtan^2x） x趋近于0
=lim 2sin^2x/（2sin^2x+xtan^2x ）x趋近于0
=lim 2/（2+x/cos^2x ）x趋近于0
=1