0
\$\begingroup\$

Here, I can't understand the third step. Why they ignored other three terms \$(40000\sin\omega t\sin 3\omega t, 10000\sin 3\omega t\sin 5\omega t, 20000\sin 5\omega t\sin\omega t)?\$ Please help.

\$\endgroup\$
0

1 Answer 1

1
\$\begingroup\$

Replace \$\sin(A)\sin(B)\$ with \$\frac{1}{2}(\cos(A-B)-\cos(A+B))\$. (Reference) Perform the integration after doing the above substitution. It will be zero since area under the curve of \$\cos(\cdot)\$ is zero over the range of integration performed.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.