Mister Exam

Derivative of sqrt(cos(7x))

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

The graph:

from to

Piecewise:

The solution

You have entered [src]
  __________
\/ cos(7*x) 
$$\sqrt{\cos{\left(7 x \right)}}$$
sqrt(cos(7*x))
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 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 answer is:

The graph
The first derivative [src]
 -7*sin(7*x)  
--------------
    __________
2*\/ cos(7*x) 
$$- \frac{7 \sin{\left(7 x \right)}}{2 \sqrt{\cos{\left(7 x \right)}}}$$
The second derivative [src]
    /                     2      \
    |    __________    sin (7*x) |
-49*|2*\/ cos(7*x)  + -----------|
    |                    3/2     |
    \                 cos   (7*x)/
----------------------------------
                4                 
$$- \frac{49 \left(\frac{\sin^{2}{\left(7 x \right)}}{\cos^{\frac{3}{2}}{\left(7 x \right)}} + 2 \sqrt{\cos{\left(7 x \right)}}\right)}{4}$$
The third derivative [src]
     /         2     \         
     |    3*sin (7*x)|         
-343*|2 + -----------|*sin(7*x)
     |        2      |         
     \     cos (7*x) /         
-------------------------------
             __________        
         8*\/ cos(7*x)         
$$- \frac{343 \left(\frac{3 \sin^{2}{\left(7 x \right)}}{\cos^{2}{\left(7 x \right)}} + 2\right) \sin{\left(7 x \right)}}{8 \sqrt{\cos{\left(7 x \right)}}}$$