第1个回答 2012-03-23
5 ∫[1,x^2]costdt=∫[1,x^2]costd(√t)^2 (u=√t) =∫[0,x]2ucos(u^2)du-∫[0,1]2ucos(u^2)du
d∫[1,x^2]costdt /dx=2xcos(x^2)
1
lim(x->0)(1/cosx-1)/x^2=lim(x->0) (sinx/cosx^2)/2x=(1/2)lim(x->0)(sinx/x)(1/cosx^2)=1/2
2
lim(x-∝)(1+2/(2x+1))^x=lim(x->∝)[(1+1/(x+1/2))^(x+1/2)]^(x/(x+1/2))=e
3
y'=[1+x/√1+x^2)]/[x+√(1+x^2)]=1/√(1+x^2)
4
y'=arcsinx+x/√1-x^2)-x/√(1-x^2)=arcsinx y''=1/√(1-x^2)本回答被网友采纳