Hm (I know excuses, escuses but...) partly because it was my first day back to school and because I have a strong headache I just dont seem to understand what I'm suppose to be doing so I would appreciate if someone could just clarify it for me:

the qu. says:

Find the values of (thetha which i'll change to X) for which the following functions have a. max. values b. minimum values

 

2 sinX+cosX

 

I differentiate first right?

and then should i just solve for 2 cosX-sinX=0?

Right, and are you given a domain? Otherwise you technically have an infinite amount of values, but maybe they just want the first positive ones.

..., but maybe they just want the first positive ones.

2sin(x)+cos(x) has the same periodicity as sin(x) and cos(x) anyways so you can in fact identify all maxima and minima.

Right, and are you given a domain?

hm no but I suppose I have to give the general solution

as a matter of fact i have the answer... just i dont think the reasoning is right because I tend to make up some impossible maths sometimes... I tell you, I get lost pretty quickly just after the differentiation