Swapnil Saxena
Last Activity: 12 Years ago
The equation can take two forms. For sin(thita)+cos(thita)>=0,it is sin(thita)+cos(thita)----(1) , But for sin(thita)+cos(thita)<0 ,it is -(sin(thita)+cos(thita))------(2)
Differentiating the equation with respect to (thita) for finding the the maxima,
(d/d(thita))(sin(thita)+cos(thita))=cos(thita)-sin(thita)
Putting the above equation equal to 0,cos(thita)-sin(thita)=0 ==> cos(thita)=sin(thita) which is only possible for (pi)/4 or 5(pi)/4 .When thita is pi/4 or 5(pie)/4, the value of the equation is (1/root(2))+(1/root(2))=root(2).(Maxima of the equation).The minima will definitely be 0 achieved when thita=3pi/4 or 7pi/4. So option (c) seems to be correct.
Note: The Mod seems to change the minima of the eqaion frm -root(2) to 0, but not the maxima