The value of the integral $$\,I = {1 \over {\sqrt {2\,\,\pi } }}\int\limits_0^\infty {\exp \left( { - {{{x^2}} \over 8}} \right)dx} $$ is

The derivative of the symmetric function drawn in Fig .1 will look like

The function x(t) is shown in Fig. Even and odd parts of a unit-step function u(t) are respectively.

A signal x(n)$$ = \sin ({\omega _0}\,n + \phi )$$ is the input to a linear time-invariant system having a frequency response $$H({e^{j\omega }})$$.If the output of the system is $$Ax(n - {n_0})$$, then the most general form of $$\angle H({e^{j\omega }})$$ will be