MATLAB编程求助

if w2<=0.64
ER=-0.000410*w2;
ERV=-0.0287*w2;

elseif 0.64<w2<=2.1
ER=0.00012*w2-0.000338;
ERV=0.0085*w2-0.0238;
elseif 2.1<w2<=7.9
ER=0.00003*w2-0.000143;
ERV=0.0021*w2-0.0104;
elseif 7.9<w2<=9.36
ER=0.00012*w2-0.00086;
ERV=0.0085*w2-0.0853;
else
ER=-0.00041*w2-0041;
ERV=0.0287*w2-0.2872;
end

这个程序段不能进入第二个以后的elseif程序，苦恼中，why？？