Найти производную функцию . 1)f(x)3x^6+x^4/4-2x^2+5x. 2)f(x)=(2-5x)√x. 3)f(x)=x^2-8x/x+2. 4)f(x)=4/x^2-5/x^4. найти уравнение касательной к графику функции f(x)=3x^2-x^3 в точке с абсциссой x0=-2. найти производную данной функции и вычислить ее значение в данной точке x0. 1) f(x)=√6x+7,x0=3. 2)f(x)cos^4x,x0=pi/4. найти уравнение касательной к графику функции f(x)=x^2-4x-10,параллельной прямой y=-6x+7.

Лебедев Дмитрий Сергеевич

Учитель математики

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Для решения данных задач воспользуемся правилами дифференцирования и формулой уравнения касательной. ️ Шаг 1: Нахождение производных функций

  1. Для функции f(x)=3x6+x442x2+5xf of x equals 3 x to the sixth power plus the fraction with numerator x to the fourth power and denominator 4 end-fraction minus 2 x squared plus 5 x применяем правило производной степени:
    f(x)=36x5+144x322x+5=18x5+x34x+5f prime of x equals 3 center dot 6 x to the fifth power plus one-fourth center dot 4 x cubed minus 2 center dot 2 x plus 5 equals 18 x to the fifth power plus x cubed minus 4 x plus 5 Для f(x)=(25x)xf of x equals open paren 2 minus 5 x close paren the square root of x end-root раскроем скобки: f(x)=2x1/25x3/2f of x equals 2 x raised to the 1 / 2 power minus 5 x raised to the 3 / 2 power.
    f(x)=212x-1/2532x1/2=1x15x2=215x2xf prime of x equals 2 center dot one-half x raised to the negative 1 / 2 power minus 5 center dot three-halves x raised to the 1 / 2 power equals the fraction with numerator 1 and denominator the square root of x end-root end-fraction minus the fraction with numerator 15 the square root of x end-root and denominator 2 end-fraction equals the fraction with numerator 2 minus 15 x and denominator 2 the square root of x end-root end-fraction Для f(x)=x28xx+2f of x equals the fraction with numerator x squared minus 8 x and denominator x plus 2 end-fraction используем правило частного (uv)=uvuvv2open paren u over v end-fraction close paren prime equals the fraction with numerator u prime v minus u v prime and denominator v squared end-fraction :
    f(x)=(2x8)(x+2)(x28x)1(x+2)2=2x2+4x8x16x2+8x(x+2)2=x2+4x16(x+2)2f prime of x equals the fraction with numerator open paren 2 x minus 8 close paren open paren x plus 2 close paren minus open paren x squared minus 8 x close paren center dot 1 and denominator open paren x plus 2 close paren squared end-fraction equals the fraction with numerator 2 x squared plus 4 x minus 8 x minus 16 minus x squared plus 8 x and denominator open paren x plus 2 close paren squared end-fraction equals the fraction with numerator x squared plus 4 x minus 16 and denominator open paren x plus 2 close paren squared end-fraction Для f(x)=4x25x4=4x-25x-4f of x equals the fraction with numerator 4 and denominator x squared end-fraction minus the fraction with numerator 5 and denominator x to the fourth power end-fraction equals 4 x to the negative 2 power minus 5 x to the negative 4 power :
    f(x)=4(-2)x-35(-4)x-5=8x3+20x5f prime of x equals 4 open paren negative 2 close paren x to the negative 3 power minus 5 open paren negative 4 close paren x to the negative 5 power equals negative the fraction with numerator 8 and denominator x cubed end-fraction plus the fraction with numerator 20 and denominator x to the fifth power end-fraction

️ Шаг 2: Уравнение касательной при x0=-2x sub 0 equals negative 2 Функция: f(x)=3x2x3f of x equals 3 x squared minus x cubed. Уравнение касательной: y=f(x0)+f(x0)(xx0)y equals f of open paren x sub 0 close paren plus f prime of open paren x sub 0 close paren open paren x minus x sub 0 close paren.

  1. Вычислим значение функции: f(-2)=3(-2)2(-2)3=3(4)(-8)=12+8=20f of negative 2 equals 3 open paren negative 2 close paren squared minus open paren negative 2 close paren cubed equals 3 open paren 4 close paren minus open paren negative 8 close paren equals 12 plus 8 equals 20. Найдем производную: f(x)=6x3x2f prime of x equals 6 x minus 3 x squared. Вычислим значение производной: f(-2)=6(-2)3(-2)2=-1212=-24f prime of negative 2 equals 6 open paren negative 2 close paren minus 3 open paren negative 2 close paren squared equals negative 12 minus 12 equals negative 24. Составим уравнение: y=2024(x+2)=2024x48=-24x28y equals 20 minus 24 open paren x plus 2 close paren equals 20 minus 24 x minus 48 equals negative 24 x minus 28.

️ Шаг 3: Вычисление производной в точке

  1. f(x)=6x+7f of x equals the square root of 6 x plus 7 end-root , x0=3x sub 0 equals 3.
    Производная сложной функции: f(x)=126x+76=36x+7f prime of x equals the fraction with numerator 1 and denominator 2 the square root of 6 x plus 7 end-root end-fraction center dot 6 equals the fraction with numerator 3 and denominator the square root of 6 x plus 7 end-root end-fraction .
    При x=3x equals 3: f(3)=363+7=325=35=0.6f prime of 3 equals the fraction with numerator 3 and denominator the square root of 6 center dot 3 plus 7 end-root end-fraction equals the fraction with numerator 3 and denominator the square root of 25 end-root end-fraction equals three-fifths equals 0.6 . f(x)=cos4xf of x equals the fourth power of cosine x, x0=π4x sub 0 equals the fraction with numerator pi and denominator 4 end-fraction .
    Производная: f(x)=4cos3x(sinx)=-4cos3xsinxf prime of x equals 4 cosine cubed x center dot open paren negative sine x close paren equals negative 4 cosine cubed x sine x.
    При x=π4x equals the fraction with numerator pi and denominator 4 end-fraction : f(π4)=-4(22)322=-422822=-4416=-1f prime of open paren the fraction with numerator pi and denominator 4 end-fraction close paren equals negative 4 open paren the fraction with numerator the square root of 2 end-root and denominator 2 end-fraction close paren cubed center dot the fraction with numerator the square root of 2 end-root and denominator 2 end-fraction equals negative 4 center dot the fraction with numerator 2 the square root of 2 end-root and denominator 8 end-fraction center dot the fraction with numerator the square root of 2 end-root and denominator 2 end-fraction equals negative 4 center dot 4 over 16 end-fraction equals negative 1 .

️ Шаг 4: Касательная, параллельная прямой y=-6x+7y equals negative 6 x plus 7 Функция: f(x)=x24x10f of x equals x squared minus 4 x minus 10. Если касательная параллельна прямой, их угловые коэффициенты равны: f(x0)=-6f prime of open paren x sub 0 close paren equals negative 6.

  1. Найдем производную: f(x)=2x4f prime of x equals 2 x minus 4. Найдем точку касания: 2x04=-62x0=-2x0=-12 x sub 0 minus 4 equals negative 6 implies 2 x sub 0 equals negative 2 implies x sub 0 equals negative 1. Значение функции в точке: f(-1)=(-1)24(-1)10=1+410=-5f of negative 1 equals open paren negative 1 close paren squared minus 4 open paren negative 1 close paren minus 10 equals 1 plus 4 minus 10 equals negative 5. Уравнение касательной: y=-56(x+1)=-56x6=-6x11y equals negative 5 minus 6 open paren x plus 1 close paren equals negative 5 minus 6 x minus 6 equals negative 6 x minus 11.

Ответ:

  1. Производные: 1. 18x^5 + x^3 - 4x + 5; 2. \frac{2-15x}{2\sqrt{x}}; 3. \frac{x^2+4x-16}{(x+2)^2}; 4. \frac{20}{x^5} - \frac{8}{x^3}.
  2. Уравнение касательной: y = -24x - 28.
  3. Значения в точках: 1. 0.6; 2. -1.
  4. Параллельная касательная: y = -6x - 11.

Нужно ли построить график какой-либо из этих функций для визуализации решения?

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