Integral of cos8x dx

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 |  cos(8*x) dx
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\int\limits_{0}^{1} \cos{\left(8 x \right)}\, dx

Integral(cos(8*x), (x, 0, 1))

Detail solution

Let $u = 8 x$ .

Then let $du = 8 dx$ and substitute $\frac{du}{8}$ :

$\int \frac{\cos{\left(u \right)}}{8}\, du$
1. The integral of a constant times a function is the constant times the integral of the function:
  
  $\int \cos{\left(u \right)}\, du = \frac{\int \cos{\left(u \right)}\, du}{8}$
  1. The integral of cosine is sine:
    
    $\int \cos{\left(u \right)}\, du = \sin{\left(u \right)}$
  So, the result is: $\frac{\sin{\left(u \right)}}{8}$
Now substitute $u$ back in:

$\frac{\sin{\left(8 x \right)}}{8}$
Add the constant of integration:

$\frac{\sin{\left(8 x \right)}}{8}+ \mathrm{constant}$

The answer is:

\frac{\sin{\left(8 x \right)}}{8}+ \mathrm{constant}

The answer (Indefinite) [src]

  /                          
 |                   sin(8*x)
 | cos(8*x) dx = C + --------
 |                      8    
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\int \cos{\left(8 x \right)}\, dx = C + \frac{\sin{\left(8 x \right)}}{8}

Simplify

The graph

Plot the graph f(x)

The answer [src]

sin(8)
------
  8

\frac{\sin{\left(8 \right)}}{8}

sin(8)
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  8

\frac{\sin{\left(8 \right)}}{8}

sin(8)/8

Numerical answer [src]

0.123669780827923

0.123669780827923

The graph

Use the examples entering the upper and lower limits of integration.