用等价代换...洛BI达法则求解1-cos(x^2) 等价于(1/2)*x^4sin(x^2)等价于x^2tanx)^2等价于x^2所以原式=1/2
1-cos(x^2) ---(1/2)*x^4 sin(x^2)---x^2 tanx)^2---x^2 结果为:1/2
