pi/4 - x > 0 for every x in (-pi/2,pi/4), so...
I am desperately stuck. I need to prove this inequality: MathBin.net - Mean value theorem inequality.
On this page you also see my feeble attempts to do it. Have to hand it in tomorrow (same ol' story, I know ) and I don't know what to do!
Thanks for any help,
@Plato: thanks for your reply. I'm not used to the sec e.o. functions, so I prefer to use sin and cos. I already worked out the mean value theorem for tan(x) using sin and cos.
@Also sprach Zarathustra (nice name BTW ):
Thanks for your answer. I think I might have it now, but I know next to nothing about inequalities.
And of course , so:
I only don't know whether this is correct. Also, why can you only multiply by 1 without changing the sign if ?
You have been a great help so far, thank you!