原式=lim((sin(x^2)/x-1)/(cos(x^2)-`1)当n→∞时 lin(sin(x^2)*(1/x))=0(为什么 因为sin(x^2)有界而1/x是无穷小啊）同理当n→∞时 lin(sin(x^2)*(1/x))=0∴原式=(lim sin(x^2)/x-1)/(lim cos(x^2)/x-1)=(0-1)/(0-1)=1
