The standard deviation of a uniformly distributed random variable $$b/w$$ $$0$$ and $$1$$ is

The solution of $$x{{dy} \over {dx}} + y = {x^4}$$ with condition $$y\left( 1 \right) = {6 \over 5}$$

The inverse Laplace transform of $${1 \over {\left( {{s^2} + s} \right)}}$$ is

An analytic function of a complex variable $$z = x + i\,y$$ is expressed as
$$f\left( z \right) = u\left( {x,y} \right) + i\,\,v\,\,\left( {x,y} \right)$$ where $$i = \sqrt { - 1} .$$
If $$u=xy$$ then the expression for $$v$$ should be