I am having problems with understanding the R formula of which I was required to self study for. I know how to convert basic equations using the formula but I have problems understanding the max and min. points.

could anyone explain to me when do I use Rcos or Rsin and $\displaystyle (\theta + or - \alpha)$ ?

It would be good if you can provide me with the graphs so I can visualise the question better.

example questions : find the maximum and minimum values of $\displaystyle 4cos\theta - 3sin\theta$ , and $\displaystyle 1 - 2sin\theta -cos\theta$ and their corresponding values of theta between 0 and 360 degrees.

sorry about the paragraphing,I'm typing from my phone.

thanks in advance