cosx立方的导数

郎彩钧835复合导数求导公式?f'(g(x))怎么导?比如cosx的1/3次方的导数?是1/3{( - sinx)的 - 2/3次方} -
边国闵19246492828 ______[答案] [f(g(x))]'=f'(g(x))*g'(x) (cosx^1/3)'=1/3cosx^(-2/3)*(-sinx)

郎彩钧835正切函数三次方导数 -
边国闵19246492828 ______[答案] y=(tanx)^3 y'=3(tanx)^2/(cosx)^2=3(sinx)^2/(cosx)^4

郎彩钧835哪个函数的导数是(cosx)^3 -
边国闵19246492828 ______[答案] cos 3x=cos 2x cos x-sin 2x sin x =cos³x-3cos x sin²x cos³x=cos 3x+3cos x sin²x ∫ cos³x dx=∫ (cos 3x+3cos x sin²x) dx =∫ cos 3x dx+∫ 3cos x sin²x dx =1/3 sin 3x+sin³x+C 也可以把sin³x变换,sin³x=3/4 sin x-1/4 sin 3x 上式=3/4 sin x+1/12 ...

郎彩钧835y=sinx^2乘以cosx^2,求导题目是y=sin平方x乘以cos平方x,进行求导,正确答案是sin2xcosx^2 - 2xsin平方xsinx^2, -
边国闵19246492828 ______[答案] 方法一: y=(sinx)^2·(cosx)^2, y'=[(sinx)^2]'·(cosx)^2+(sinx)^2·[(cosx)^2]' =2sinx·(sinx)'·(cosx)^2+(sinx)^2·2cox·(cosx)' =2sinx(cosx)^3-2(sinx)^3cosx 备注:化简看看 =2sinxcosx[(cox)^2-(sinx)^2] =sin2x·cos2x =1/2·2sin2xcos2x =1/2 ·sin4x ...

郎彩钧835y=(cosx)三次方,,求Y的N次求导...追50分,如题...3/4 COS(X+N PI/2)+(3/4)^N COS (3X+N PI/2) -
边国闵19246492828 ______[答案] cos3x = 4(cosx)^3 - 3cosxy = (cosx)^3 = 1/4 * (cos3x) + 3/4 * cosx(cosx)' = -sinx = cos(x+Pi/2)(cosx)'' = - cosx = cos(x+2*Pi/2)(cosx)n次导 = cos(x + n * Pi/2)y(n次导) = 3/4 * cos(x + n*Pi/2) + 1/4 * ...

郎彩钧835x平方除以cosx的导数 -
边国闵19246492828 ______[答案] 导数是 [(cosx * 2x) - x^2 * (-sinx)] / (cosx)^2 分子: [(cosx * 2x) - x^2 * (-sinx)] 分母: (cosx)^2 ^2这个符号是平方, *是乘号.

郎彩钧835求函数y=x+1分子x和函数y=x分之ex次方cosx的导数求大神帮助 -
边国闵19246492828 ______[答案] 1、y=x^2/(x+1),则y'=(2x-x^2)/(x+1)^2=x(2-x)/(x+1)^2 2、y=e^cosx/x,则y'=(-sinx*e^cosx*x-e^cosx)/x^2 =-e^cosx*(xsinx+1)/x^2

郎彩钧835求函数y=3x的平方 xcosx的导数过程 -
边国闵19246492828 ______[答案] y=3x²+xcosx y′=6x+x′cosx+x(cosx)′ =6x+cosx+x(-sinx) =6x+cosx-xsinx

郎彩钧835导数最大值f(X)=cos立方X+sin平方X - cosX上最大值等于? -
边国闵19246492828 ______[答案] f(x)=cosx[-(sinx)^2]+(sinx)^2 =(1-cosx)[1-(cosx)^2] 令t=cosx, 得f(t)=(1-t)(1-t^2) =t^3-t^2-t+1 ∴f'(t)=3t^2-2t-1 =(t-1)(3t+1) ∴f'(x)在区间(-1,-1/3)上为正,在(-1/3,1)上为负. 即在t=-1/3处f(x)取得最大值,最大值是32/27. 是吗?是吧!

郎彩钧8354cos三次方x - 3cosx为什么化成cos3x -
边国闵19246492828 ______[答案] consider (cosx+isinx)^3 =(cosx)^3-3(cosx)sinx + i(3(cosx)^2sinx -(sinx)^3) cos3x+isin3x=(cosx)^3-3(cosx)(sinx)^2 + i(3(cosx)^2sinx -(sinx)^3) 实数部分 cos3x= (cosx)^3-3(cosx)(sinx)^2 = 4(cosx)^3 - 3cosx( (cosx)^2+(sinx)^2) =4(cosx)^3 - 3cosx