高数微分计算如图题目?
f(x)
=x^2.e^(-x^2) ; |x|≤1
=1/e ; |x|>1
f(1)
=f(1-)
=lim(x->1-) x^2.e^(-x^2)
=1/e
f(1+)=1/e = f(1-)
x=1, f(x) 连续
f'(1+)
=lim(h->0) [1/e - f(1) 尘物慧]/h
=0
f'(1-)
=lim(h->0) [ (1+h)^2.e^(-(1+h)^2) - f(1) ]/h
=lim(h->0) [ (1+h)^2.e^(-(1+h)^2) - 1/e ]/h
=lim(h->0) [ (1+h)^2.e^(-1-2h-h^2) - 1/e ]/h
=lim(h->0) 蚂隐[ (1+h)^2.e^(-2h-h^2) - 1 ]/(e.h)
(1+h)^2.e^(-2h-h^2) 等价于(1-h)
=lim(h->0) [ (1-h) - 1 ]/(e.h)
=lim(h->0) -h/(e.h)
=-1/e
≠f'(1+)
x=1, f(x) 不可导
//
同样的可以得到
x=-1, f(x) 连续
x=-1, f(x) 不可导
ie
f'(x)
=(2x - 2x^3) .e^(-x^2) 派答 ; |x|<1
=0 ; |x| >1
x=1 or -1 , f'(x) 不存在