求 f concave upward 和 downward的范围图像是原函数,要导两次就晕了－ －

求 f concave upward 和 downward的范围（c）和（d）三道题 求 f concave upward 和 downward的范围图像是原函数,要导两次就晕了－ － 微积分concave up and downf(x)=(x^2)/(x^2+3)(c) On what interval(s) is f concave upward?On what interval(s) is f concave downward?What are the x-coordinate(s) of the inflection point(s) of concave On what interval is the curve y = x ln(x - 1) concave upward? 求高手解救!什么是downward initiated lightning 和 upward initiated lightning?（电气雷击保护出现的 微积分求Concave up和Concave down是不是二次求导后设它等于0,我算到正负(44/242)^(1/2),但不知道区间范围,又不知道有没有算错.还要求垂直渐近线和水平渐近线分别是多少 upward bound 求翻译In the LEO,the force of gravity decreases upward by 0.33 μg/m upward appraisal是什么意思 upward mobility是什么意思 onward and upward是什么意思 关于凸函数,凹函数的证明题求助!急~~~~~!Let f(x) be a function on R^n. Prove that f is both convex and concave if and only if f(x)=(c^T)x+b for some vector c and scalar b.翻译：f(x)是R^n上一函数.证明f既是凸函数也是凹函 onward and upward等于 全力以赴的 意思 设f(x)= 1-x分之x 求f[(fx)]和f{f[f(x)]} f(x1+x2)=f(x1)f(x2),f’(0)=2,求f(x)和f’(x) He lay on his back, his teeth set, his right hand clenched on his breast and his glaring eyes （looking ）straight upward.为什么括号里用现在分词?求解释!谢谢 设f(t)的傅里叶变化为F(jω),求F(0)和f(0).