The general value of  $\theta$ satisfying the equation  ${2\sin }^2\theta -3\sin \theta -2=0$ , is

Let $\left[x\right]$ be the greatest integer less than or equal to $x$, for a real number $x$. Then the following sum

$\left[\frac{2^{2020}+1}{2^{2018}+1}\right]+\left[\frac{3^{2020}+1}{3^{2018}+1}\right]+\left[\frac{4^{2020}+1}{4^{2018}+1}\right]+\left[\frac{5^{2020}+1}{5^{2018}+1}\right]+\left[\frac{6^{2020}+1}{6^{2018}+1}\right]$

is :-

Let $f:R\to R$ be defined by $f\left(x\right)=\left\{\begin{array}{lll}2x& ;x>3& \\ x^2& ;1<x\le 3& \\ 3x& ;x\le 1& \end{array}\right.$ 

Then $f\left(-1\right)+f\left(2\right)+f\left(4\right)$ is