limx趋近于0 (根号2-根号下1+cosx)除以sinx的平方
2个回答

lim(x→0) [√2-√(1+cosx)]/(sinx)^2

lim(x→0) [√2-√(1+cosx)]=0

lim(x→0) (sinx)^2=0

=lim(x→0) [√2-√2|cos(x/2)| ]/(sinx)^2

lim(x→0) [√2-√2|cos(x/2)| ]=0

lim(x→0)(sinx)^2=0

=lim(x→0) [√2-√2|cos(x/2)|]'/(sinx)^2 '

=lim(x→0) (-√2/2)|sin(x/2)|]/2sinxcosx

=lim(x→0) (√2/2)/[4cosx*cos(x/2)]

=√2/8