Derivative of xtg^3x

The solution

You have entered [src]

     3   
x*tan (x)

$$x \tan^{3}{\left(x \right)}$$

x*tan(x)^3

Detail solution

Apply the product rule:

$\frac{d}{d x} f{\left(x \right)} g{\left(x \right)} = f{\left(x \right)} \frac{d}{d x} g{\left(x \right)} + g{\left(x \right)} \frac{d}{d x} f{\left(x \right)}$

$f{\left(x \right)} = x$ ; to find $\frac{d}{d x} f{\left(x \right)}$ :
1. Apply the power rule: $x$ goes to $1$
$g{\left(x \right)} = \tan^{3}{\left(x \right)}$ ; to find $\frac{d}{d x} g{\left(x \right)}$ :
1. Let $u = \tan{\left(x \right)}$ .
2. Apply the power rule: $u^{3}$ goes to $3 u^{2}$
3. Then, apply the chain rule. Multiply by $\frac{d}{d x} \tan{\left(x \right)}$ :
  1. Rewrite the function to be differentiated:
    
    $\tan{\left(x \right)} = \frac{\sin{\left(x \right)}}{\cos{\left(x \right)}}$
  2. Apply the quotient rule, which is:
    
    $\frac{d}{d x} \frac{f{\left(x \right)}}{g{\left(x \right)}} = \frac{- f{\left(x \right)} \frac{d}{d x} g{\left(x \right)} + g{\left(x \right)} \frac{d}{d x} f{\left(x \right)}}{g^{2}{\left(x \right)}}$
    
    $f{\left(x \right)} = \sin{\left(x \right)}$ and $g{\left(x \right)} = \cos{\left(x \right)}$ .
    
    To find $\frac{d}{d x} f{\left(x \right)}$ :
    1. The derivative of sine is cosine:
      
      $\frac{d}{d x} \sin{\left(x \right)} = \cos{\left(x \right)}$
    To find $\frac{d}{d x} g{\left(x \right)}$ :
    1. The derivative of cosine is negative sine:
      
      $\frac{d}{d x} \cos{\left(x \right)} = - \sin{\left(x \right)}$
    Now plug in to the quotient rule:
    
    $\frac{\sin^{2}{\left(x \right)} + \cos^{2}{\left(x \right)}}{\cos^{2}{\left(x \right)}}$
  The result of the chain rule is:
  
  $\frac{3 \left(\sin^{2}{\left(x \right)} + \cos^{2}{\left(x \right)}\right) \tan^{2}{\left(x \right)}}{\cos^{2}{\left(x \right)}}$
The result is: $\frac{3 x \left(\sin^{2}{\left(x \right)} + \cos^{2}{\left(x \right)}\right) \tan^{2}{\left(x \right)}}{\cos^{2}{\left(x \right)}} + \tan^{3}{\left(x \right)}$
Now simplify:

$\frac{3 x \sin^{2}{\left(x \right)}}{\cos^{4}{\left(x \right)}} + \tan^{3}{\left(x \right)}$

The answer is:

$\frac{3 x \sin^{2}{\left(x \right)}}{\cos^{4}{\left(x \right)}} + \tan^{3}{\left(x \right)}$

The graph

Plot the graph f(x)

Plot the graph f'(x)

The first derivative [src]

   3           2    /         2   \
tan (x) + x*tan (x)*\3 + 3*tan (x)/

$$x \left(3 \tan^{2}{\left(x \right)} + 3\right) \tan^{2}{\left(x \right)} + \tan^{3}{\left(x \right)}$$

Simplify

The second derivative [src]

  /       2   \ /  /         2   \         \       
6*\1 + tan (x)/*\x*\1 + 2*tan (x)/ + tan(x)/*tan(x)

$$6 \left(x \left(2 \tan^{2}{\left(x \right)} + 1\right) + \tan{\left(x \right)}\right) \left(\tan^{2}{\left(x \right)} + 1\right) \tan{\left(x \right)}$$

Simplify

The third derivative [src]

                /  /             2                                      \                           \
  /       2   \ |  |/       2   \         4           2    /       2   \|     /         2   \       |
6*\1 + tan (x)/*\x*\\1 + tan (x)/  + 2*tan (x) + 7*tan (x)*\1 + tan (x)// + 3*\1 + 2*tan (x)/*tan(x)/

$$6 \left(x \left(\left(\tan^{2}{\left(x \right)} + 1\right)^{2} + 7 \left(\tan^{2}{\left(x \right)} + 1\right) \tan^{2}{\left(x \right)} + 2 \tan^{4}{\left(x \right)}\right) + 3 \left(2 \tan^{2}{\left(x \right)} + 1\right) \tan{\left(x \right)}\right) \left(\tan^{2}{\left(x \right)} + 1\right)$$

Simplify

Other calculators

How to use it?

Identical expressions

Derivative of xtg^3x

The graph:

Piecewise:

The solution