If $A={\sin }^{28}\theta +{\cos }^{36}\theta$ then

Given that $A={\sin }^{28}\theta +{\cos }^{36}\theta$

We K.T ${\sin }^{28}\theta \le {\sin }^2\theta$

${\cos }^{36}\theta \le {\cos }^2\theta$

$\begin{array}{l}\Rightarrow {\sin }^{28}\theta +{\cos }^{36}\theta \le {\sin }^2\theta +{\cos }^2\theta \\ \Rightarrow {\sin }^{28}\theta +{\cos }^{36}\theta \le 1\\ \Rightarrow A\le 1\end{array}$

$We\text{ KT A>0}\therefore 0<A\le 1$