Which of the following is an example of Disciflorae?

Dry distillation of calcium acetate and calcium formate forms:

$P$ is a point on the segment joining the feet of two vertical poles of heights $a$ and $b$. The angles of elevation of the tops of the poles from $P$ are $45^{\circ}$ each. Then,the square of the distance between the tops of the poles is

Which one of the following statements is not correct?

$A$ particle moves with simple harmonic motion in a straight line. In the first $\tau \, s$,after starting from rest,it travels a distance $a$,and in the next $\tau \, s$,it travels $2a$ in the same direction. Then:

$\int_{-\pi / 2}^{\pi / 2} \sin |x| \, dx$ is equal to