Which of the following is an antidiabetic drug?

$\operatorname{cosec} 15^{\circ} + \sec 15^{\circ}$ is equal to :

If $x-y+1=0$ meets the circle $x^2+y^2+y-1=0$ at $A$ and $B$,then the equation of the circle with $AB$ as diameter is

Assume that a drop of liquid evaporates by decrease in its surface energy,so that its temperature remains unchanged. What should be the minimum radius of the drop for this to be possible? The surface tension is $T$,density of liquid is $\rho$ and $L$ is its latent heat of vaporization.

$CrO_3$ dissolves in aqueous $NaOH$ to give:

$ECG$ depicts the depolarization and repolarization processes during the cardiac cycle. In the $ECG$ of a normal healthy individual,one of the following waves is not represented?