导数50题大全及答案

贝饼诗4283方向导数题函数u=xy2+z3 - xyz在点P0=(0, - 1,2)沿方向l=(1,根号2,1) 的方向导数是多少,答案是15/2,但我算得是(11 - 3根号2)/2,难道算错? -
国饱肯18336327016 ______[答案] cosα = 1/√(1+2+1) = 1/2 cosβ = √2/√(1+2+1) = √2/2 cosγ = 1/√(1+2+1) = 1/2 ∂u/∂x = y² - yz = 3 ∂u/∂y = 2xy - xz = 0 ∂u/∂z = 3z² - xy = 12 方向导数 =1/2 * 3 + √2/2 * 0 + 1/2 * 12 =15/2

贝饼诗4283求x^2sin2x的50阶导数 -
国饱肯18336327016 ______[答案] (uv)'=u'v+uv'(uv)''=((uv)')'=(u'v+uv')'= u''v+u'v'+u'v'+uv''=u''v+2u'v'+uv''(uv)'''=(u''v+2u'v'+uv'')'=(u'''v+u''v'')+(2u''v'+2u'v'')+(uv'''+u'v'')=u'''v+3u''v'+3u'v''+uv'''(uv)(n) = C(0,n)u(0)v(n)+C(...

贝饼诗4283y=x^2sin2x,求y的50阶导数 -
国饱肯18336327016 ______[答案] (uv)'=u'v+uv'(uv)''=((uv)')'=(u'v+uv')'= u''v+u'v'+u'v'+uv''=u''v+2u'v'+uv''(uv)'''=(u''v+2u'v'+uv'')'=(u'''v+u''v'')+(2u''v'+2u'v'')+(uv'''+u'v'')=u'''v+3u''v'+3u'v''+uv'''(uv)(n) = C(0,n)u(0)v(n)+C(...

贝饼诗4283导数的题要过程不要讲解设常数a>=0,函数f(x)=x - (lnx)^2+2alnx - 1(x>0)(1)令g(x)=xf'(x)(x>0),求g(x)的最小值与零的大小(2)求证:f(x)在(0,正无穷)上... -
国饱肯18336327016 ______[答案] f'(x)=1-2(lnx)/x+2a/x (1)g(x)=x-2lnx+2a,g'(x)=1-2/x,g＂(x)=2/x^2>0,所以g(x)是凹函数.因此g(x)在x=2有最小值2-2ln2+2a>0 (2)f＂(x)=-2/x^2+2(lnx)/x^2-2a/x^2=-2(1-lnx+2a)/x^2=0,x=e^(2a+1),当x≥e^(2a+1),f＂(x)≥0,在0

贝饼诗4283高数题求导数Y=e^ - x(x^2 - 2x+3)求导数答案是e^ - x( - x^2+4x - 5) -
国饱肯18336327016 ______[答案] 复合函数求导 y'=(e^-x)'*(x^2-2x+3)+e^(-x)*(x^2-2x+3)' =-e^(-x)*(x^2-2x+3)+e^(-x)*(2x-2) =e^(-x)*(2x-2-x^2+2x-3) =e^(-x)*(-x^2+4x-5)

贝饼诗4283做一道导数微积分简单题y= 4x/[根号下(x^2+15)]的f'(x)和 f''(x) -
国饱肯18336327016 ______[答案] f'(x)=60/(x^2+15)^(3/2) f''(x)=-180x/(x^2+15)^(5/2)

贝饼诗4283急!导数的概念及导数的运算题,求解答已知函数f(x)=x^3 - 3x^2 - 9x+a,求f(x)的单调区间 -
国饱肯18336327016 ______[答案] f'(x)=3x^2-6x-9有两根-1,3 故增区间为:(-∞,-1)并(3,+∞) 减区间为:(-1,3)

贝饼诗4283计算高阶导数Fx=x^2 * sin2x 求Fx的50阶导数 -
国饱肯18336327016 ______[答案] 用莱布尼茨公式 f(50)(x)=C(50,0)x^2*(sin2x)^(50)+C(50,1)(x^2)'*(sin2x)^(49)+C(50,2)(x^2)''*(sin2x)^(48) =-2^50*x^2*sin(2x)+100*2^49*xcos2x+2*50*49/2*2^48*sin2x

贝饼诗4283y=(x^2+2x+1)sin2x的50阶导数求y的50阶导数将π带进去的值 -
国饱肯18336327016 ______[答案] 两个函数相乘的高阶导数:利用公式.y∧(n)={C(上i下n)*f(x)∧(i)*g(x)∧(n-i)【求i=0到i=n的和】}.求出答案即可.

贝饼诗4283一道数学导数题1、数y=cos2x/(sinx - cosx)的导数
国饱肯18336327016 ______ 1.y=cos2x/(sinx-cosx)=[(cosx)^2-(sinx)^2]/(sinx-cosx) =-sinx-cosx 所以 y′=-cosx+sinx 2.点M(3.1415926......,0)就是点(π,0) 切线方程的斜率 k=y′│(x=π) =4cos4x│(x=π) =4 所以切线方程为 y=4(x-π) 这种题目其实不难,关键在于你能不能灵活运用公式.