Which logic gate is represented by the following combination of logic gates?

$\int \frac{3^x dx}{\sqrt{9^x-1}}$ is equal to

The solution of the differential equation $x y^2 d y - (x^3 + y^3) d x = 0$ is

$A$ neutron makes a head-on elastic collision with a stationary deuteron. The fractional energy loss of the neutron in the collision is

If $\overrightarrow{u}=\overrightarrow{a}-\overrightarrow{b}$, $\overrightarrow{v}=\overrightarrow{a}+\overrightarrow{b}$, $|\overrightarrow{a}|=|\overrightarrow{b}|=2$, then $|\overrightarrow{u} \times \overrightarrow{v}|$ is equal to

$A$ transistor is connected in common emitter $(CE)$ configuration. The collector supply is $8 \ V$ and the voltage drop across a resistor of $800 \ \Omega$ in the collector circuit is $0.5 \ V$. If the current gain factor $\alpha$ is $0.96$,find the base current in $\mu A$.