The maximum value of $$\sin \left( {x + {\pi \over 5}} \right) + \cos \left( {x + {\pi \over 5}} \right)$$, where $$x \in \left( {0,{\pi \over 2}} \right)$$, is attained at

What is the maximum value of $$16\sin \theta - 12{\sin ^2}\theta $$ ?

What is tan25$$^\circ$$ tan15$$^\circ$$ + tan15$$^\circ$$ tan50$$^\circ$$ + tan25$$^\circ$$ tan50$$^\circ$$ equal to?

What is $$\cot A + \cos ecA$$ equal to?