$$2n\pi ;\,n = 0,\, \pm 1,\, \pm 2....$$

$$x = 2n\pi + \pi /2;\,n = 0,\, \pm 1,\, \pm 2....$$

$$x = n\pi + {\left( { - 1} \right)^n}\,\,\,\,\,\,\,{\pi \over 4} - {\pi \over 4}$$ ; $$n = 0,\, \pm 1,\, \pm 2..$$

none of these

$$1 \le A \le 2$$

$${3 \over 4} \le A \le 1$$

$${13\over 16} \le A \le 1$$

$${3 \over 4} \le A \le {{13} \over {16}}$$

no real solution

one real solution

more than one solution

none of these

$$ - {4 \over 5}\,but\,not\,{4 \over 5}$$

$$ - {4 \over 5}\,or\,{4 \over 5}$$

$${4 \over 5}\,\,but\,not\, - {4 \over 5}$$

None of these.