Mister Exam

Other calculators


log(cos(2*x))^(1/2)

Derivative of log(cos(2*x))^(1/2)

Function f() - derivative -N order at the point
v

The graph:

from to

Piecewise:

The solution

You have entered [src]
  _______________
\/ log(cos(2*x)) 
$$\sqrt{\log{\left(\cos{\left(2 x \right)} \right)}}$$
d /  _______________\
--\\/ log(cos(2*x)) /
dx                   
$$\frac{d}{d x} \sqrt{\log{\left(\cos{\left(2 x \right)} \right)}}$$
Detail solution
  1. Let .

  2. Apply the power rule: goes to

  3. Then, apply the chain rule. Multiply by :

    1. Let .

    2. The derivative of is .

    3. Then, apply the chain rule. Multiply by :

      1. Let .

      2. The derivative of cosine is negative sine:

      3. Then, apply the chain rule. Multiply by :

        1. The derivative of a constant times a function is the constant times the derivative of the function.

          1. Apply the power rule: goes to

          So, the result is:

        The result of the chain rule is:

      The result of the chain rule is:

    The result of the chain rule is:

  4. Now simplify:


The answer is:

The graph
The first derivative [src]
        -sin(2*x)         
--------------------------
           _______________
cos(2*x)*\/ log(cos(2*x)) 
$$- \frac{\sin{\left(2 x \right)}}{\sqrt{\log{\left(\cos{\left(2 x \right)} \right)}} \cos{\left(2 x \right)}}$$
The second derivative [src]
 /         2                  2            \ 
 |    2*sin (2*x)          sin (2*x)       | 
-|2 + ----------- + -----------------------| 
 |        2            2                   | 
 \     cos (2*x)    cos (2*x)*log(cos(2*x))/ 
---------------------------------------------
                _______________              
              \/ log(cos(2*x))               
$$- \frac{\frac{2 \sin^{2}{\left(2 x \right)}}{\cos^{2}{\left(2 x \right)}} + 2 + \frac{\sin^{2}{\left(2 x \right)}}{\log{\left(\cos{\left(2 x \right)} \right)} \cos^{2}{\left(2 x \right)}}}{\sqrt{\log{\left(\cos{\left(2 x \right)} \right)}}}$$
The third derivative [src]
 /                         2                   2                          2           \          
 |          6         8*sin (2*x)         3*sin (2*x)                6*sin (2*x)      |          
-|8 + ------------- + ----------- + ------------------------ + -----------------------|*sin(2*x) 
 |    log(cos(2*x))       2            2         2                2                   |          
 \                     cos (2*x)    cos (2*x)*log (cos(2*x))   cos (2*x)*log(cos(2*x))/          
-------------------------------------------------------------------------------------------------
                                               _______________                                   
                                    cos(2*x)*\/ log(cos(2*x))                                    
$$- \frac{\left(\frac{8 \sin^{2}{\left(2 x \right)}}{\cos^{2}{\left(2 x \right)}} + 8 + \frac{6 \sin^{2}{\left(2 x \right)}}{\log{\left(\cos{\left(2 x \right)} \right)} \cos^{2}{\left(2 x \right)}} + \frac{6}{\log{\left(\cos{\left(2 x \right)} \right)}} + \frac{3 \sin^{2}{\left(2 x \right)}}{\log{\left(\cos{\left(2 x \right)} \right)}^{2} \cos^{2}{\left(2 x \right)}}\right) \sin{\left(2 x \right)}}{\sqrt{\log{\left(\cos{\left(2 x \right)} \right)}} \cos{\left(2 x \right)}}$$
The graph
Derivative of log(cos(2*x))^(1/2)