which calculation is correct? Examp11.8Sadiku

Hi

I'm really puzzled. I was looking at an example in a book. Just out of curiosity I was checking the calculation done in the book on my calculator and there is a huge difference between the result reached in the book and by my calculator. Please let me know what you think. Is my calculator faulty?

Regards
PG

I'm . My calculator was in degree mode and that was giving me an error! Note to the reader, always check your calculator for angle mode when doing calculus. I will continue this thread for some other problem. Sorry. And thanks for giving it a look.

Best wishes
PG

Hello,

In my opinion, a calculator will only waste your time in this kind of problems... You can't afford to lose time calculating Sin(2pi), or Cos(pi), Cos(pi/3) , Cos(5pi/6), etc...