# AS Trignomerty Help!

• March 29th 2008, 03:45 AM
looi76
AS Trignomerty Help!
Find the maximum value and minimum value of each of the following functions. Give the least positive values of x at which they occur.

$\frac{30}{11-5cos(\frac{1}{2}x-45)}$
• March 29th 2008, 03:55 AM
Moo
Hello,

$\forall x \ , \ -1 \leq cos(x) \leq 1$

Hence the function will be minimal when the denominator will be maximal, that is to say when cos(1/2 x -45) will be minimal, ie = -1

cos(1/2 x-45)=-1=cos(pi)

-> x/2 -45=pi+2kpi

-> x=2pi+90+4kpi=(4k+2)pi + 90

So you have to find k such as x is positive and the least positive.