English

1 X 3

Advertisements
Advertisements

Question

\[\frac{1}{x^3}\]

Advertisements

Solution

\[ \frac{d}{dx}\left( f(x) \right) = \lim_{h \to 0} \frac{f\left( x + h \right) - f\left( x \right)}{h}\]
\[ = \lim_{h \to 0} \frac{\frac{1}{(x + h )^3} - \frac{1}{x^3}}{h}\]
\[ = \lim_{h \to 0} \frac{x^3 - (x + h )^3}{h(x + h )^3 x^3}\]
\[ = \lim_{h \to 0} \frac{x^3 - x^3 - 3 x^2 h - 3x h^2 - h^3}{h(x + h )^3 x^3}\]
\[ = \lim_{h \to 0} \frac{- 3 x^2 h - 3x h^2 - h^3}{h(x + h )^3 x^3}\]
\[ = \lim_{h \to 0} \frac{h\left( - 3 x^2 - 3xh - h^2 \right)}{h(x + h )^3 x^3}\]
\[ = \lim_{h \to 0} \frac{\left( - 3 x^2 - 3xh - h^2 \right)}{(x + h )^3 x^3}\]
\[ = \frac{- 3 x^2}{x^6}\]
\[ = \frac{- 3}{x^4}\]
\[ = - 3 x^{- 4} \]
\[\]

shaalaa.com
  Is there an error in this question or solution?
Chapter 30: Derivatives - Exercise 30.2 [Page 25]

APPEARS IN

R.D. Sharma Mathematics [English] Class 11
Chapter 30 Derivatives
Exercise 30.2 | Q 1.03 | Page 25

Video TutorialsVIEW ALL [1]

RELATED QUESTIONS

Find the derivative of (5x3 + 3x – 1) (x – 1).


Find the derivative of x–4 (3 – 4x–5).


Find the derivative of the following function (it is to be understood that a, b, c, d, p, q, r and s are fixed non-zero constants and m and n are integers):

(x + a)


Find the derivative of the following function (it is to be understood that a, b, c, d, p, q, r and s are fixed non-zero constants and m and n are integers):

(ax + b) (cx + d)2


Find the derivative of f (x) = 99x at x = 100 


Find the derivative of f (xx at x = 1

 


\[\frac{1}{\sqrt{x}}\]


k xn


\[\frac{1}{\sqrt{3 - x}}\]


\[\frac{2x + 3}{x - 2}\] 


x ex


Differentiate of the following from first principle:

(−x)−1


Differentiate of the following from first principle:

 x cos x


Differentiate each of the following from first principle:

 x2 sin x


Differentiate each of the following from first principle:

\[e^\sqrt{ax + b}\]


Differentiate each of the following from first principle:

\[3^{x^2}\]


ex log a + ea long x + ea log a


\[\frac{2 x^2 + 3x + 4}{x}\] 


\[\frac{a \cos x + b \sin x + c}{\sin x}\]


cos (x + a)


\[If y = \sqrt{\frac{x}{a}} + \sqrt{\frac{a}{x}}, \text{ prove that } 2xy\frac{dy}{dx} = \left( \frac{x}{a} - \frac{a}{x} \right)\]  


x2 ex log 


xn tan 


(x sin x + cos x) (x cos x − sin x


x3 ex cos 


x4 (5 sin x − 3 cos x)


Differentiate each of the following functions by the product rule and the other method and verify that answer from both the methods is the same.

(3 sec x − 4 cosec x) (−2 sin x + 5 cos x)


\[\frac{1}{a x^2 + bx + c}\] 


\[\frac{\sqrt{a} + \sqrt{x}}{\sqrt{a} - \sqrt{x}}\] 


\[\frac{p x^2 + qx + r}{ax + b}\]


\[\frac{ax + b}{p x^2 + qx + r}\] 


Write the value of \[\lim_{x \to c} \frac{f(x) - f(c)}{x - c}\] 


If \[\frac{\pi}{2}\] then find \[\frac{d}{dx}\left( \sqrt{\frac{1 + \cos 2x}{2}} \right)\]


If f (x) = |x| + |x−1|, write the value of \[\frac{d}{dx}\left( f (x) \right)\]


Mark the correct alternative in  of the following:

If\[f\left( x \right) = 1 - x + x^2 - x^3 + . . . - x^{99} + x^{100}\]then \[f'\left( 1 \right)\] 


Mark the correct alternative in  of the following:
If\[f\left( x \right) = 1 + x + \frac{x^2}{2} + . . . + \frac{x^{100}}{100}\] then \[f'\left( 1 \right)\] is equal to 


Mark the correct alternative in of the following: 

If f(x) = x sinx, then \[f'\left( \frac{\pi}{2} \right) =\] 


Find the derivative of x2 cosx.


`(a + b sin x)/(c + d cos x)`


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×