Question

how did they get

Answer 1

https://gyazo.com/6d30211480b5b462920c3422c3b34ec4

Answer 2

I dont underestand how they got this:
https://gyazo.com/eec65af84bb1fd9cde28b386bf62caaa

Answer 3

is that an integral properoty

Answer 4

days of fourier series. >.<

Answer 5

integral of 0 is just 0...

Answer 6

\[\frac{1}{L}\int_{-L}^L f(x) = \frac{1}{2}\int_{-2}^2f(x)\]Probably used the periodicity of the function?

Answer 7

\[
\int_1^20\,dx=[c]_1^2=c-c=0\\
\frac{d}{dx}c=0
\]

Answer 8

read it again and pay attention to how they break up th eintervals of integration, first by symmetry then into 1's and 0's.

Answer 9

i mean integartion limts
like 2 to 0
then they got
1 to 0
then 2 to 1