If ${\cos ^{ - 1}}\,x\, - \,{\cos ^{ - 1}}\,\frac{y}{2}\, = \,\alpha ,$ where $ - {\kern 1pt} 1\, \le \,x\, \le \,1,\,$ $- {\kern 1pt} 2\, \le \,y\, \le \,2,$ $x\, \le \,\,\frac{y}{2},$ then for all $x, y, 4x^2 -4xy\,\,cos\,\alpha + y^2$ is equal to
→If $f\left( x \right)\left\{ {\begin{array}{*{20}{c}}
{\frac{{\sin \,\left( {p + 1} \right)x + \sin \,x}}{x},\,\,}&{x < 0} \\
{q\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,,}&{x = 0} \\
{\frac{{\sqrt {x + {x^2}} - \sqrt x }}{{x/2}},}&{x > 0}
\end{array}} \right.$ Is continuous at $x = 0$, then the ordered pair $(p, q)$ is equal to
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