A generator at a regional Power Station produces an alternating voltage, according to the function, 𝑉 below:

? = 240sin(2?)

An electrical engineer needs to determine when this generator will have a voltage that is exactly +120 V.

i) How many times in the interval 0 ? ? ? 2? will the voltage reach +120 V?

ii) Determine the exact times when this occurs for 0 ? ? ? 2?.

I would like the answer to ii) with workings so I can see how it is done, I do not need i) answered.
Thanks

Answer

Answers can be viewed only if
  1. The questioner was satisfied and accepted the answer, or
  2. The answer was disputed, but the judge evaluated it as 100% correct.
View the answer

1 Attachment

  • Leave a comment if you need any clarifications.

  • Hi Philip, I believe that two of the solutions above produce a negative 120v, where we need the 4 times the voltage is a positive 120. Could you clarify further for me? Thanks!

  • I managed to see from your solution that positive 120 was just occuring pi/12 seconds on the other side of the x intercept to negative 120v. Wouldn't have got there without your help though, thank you!

  • Hi Kyshogle, I had unconsciously solved the equation 240cos(2t)=120. Sorry about that. Attached is the solution for 240sin (2t)=120. I apologize for any inconvenience this may have caused.

The answer is accepted.