If $z = 3 + 5i$,then $z^3 + \bar{z} + 198$ is equal to

The angle between the curves $y=\sin x$ and $y=\cos x$ is

The function $f(x) = |x| + \frac{|x|}{x}$ is

$A$ vibrating string of certain length $l$ under a tension $T$ resonates with a mode corresponding to the first overtone (third harmonic) of an air column of length $75\, cm$ inside a tube closed at one end. The string also generates $4\, beats$ per second when excited along with a tuning fork of frequency $n$. Now when the tension of the string is slightly increased,the number of beats reduces to $2\, per second$. Assuming the velocity of sound in air to be $340\, m/s$,the frequency $n$ of the tuning fork in $Hz$ is

The major product of the following reaction is:

Which of the following is not a secondary messenger?