打電話回家
Derivatives of sin x, cos x, tan x, e^x and ln x | Product and quotient rules | Khan Academy星期六早上,老王打完了高爾夫球後,突然想到忘記告訴老婆有個修理洗衣機的工人要到他們家,於是就匆忙趕回俱樂部打公共電話回家。「 喂,是誰?」電話傳來一個小女孩的聲音。 「喂,我是老爸,妳叫媽媽接一下好嗎?」「媽媽跟陳叔叔在房間裡,我去叫她。」「甚麼!哪有甚麼陳叔叔!?」老王可急了,想要知道是Here is a proof of the derivative of sin x. d/dx (sin x) = lim h→ 0 (1/h) [sin(x+h) - sin (x) ] _by definition of derivative_. _Using the angle sum identity: sin(x+h) = sin(h) cos(x) + cos(h) sin(x)_ d/dx(sin x) = lim h→ 0 (1/h) { sin(h) cos(x)+cos(h) sin...
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