设 f(x)为å¯å¯¼ç
å¶å½æ°.f(x)=f(-x)
g(x)为f(x)ç
导å½æ°.
对äºä»»æçèªåéä½ç½® x0
g(x0) = lim[f(x0+dx)-f(x0)]/dx
g(-x0) = lim[f(-x0+dx)-f(-x0)]/dx = lim[f(x0-dx)-f(x0))/dx
f(x)å¯å¯¼,å
¶å·¦å³å¯¼æ°ç¸ç.
å³ï¼lim[f(x0+dx)-f(x0)]/dx = lim[f(x0)-f(x0-dx)]/dx
ä¸é¢è¿ä¸ªçå¼ä¸,å·¦ç«¯å°±æ¯ g(x0)ç表达å¼,èå³ç«¯å³ä¸º -g(-x0)ç表达å¼.
å³ g(x0) = - g(-x0)
x0 å
·å¤ä»»ææ§,å æ¤ g(x) = - g(-x)
å³å¨ f(x)æ¯å¯å¯¼å¶å½æ°åæä¸,å
¶å¯¼å½æ°æ¯
å¥å½æ°.