Which of the following alkenes does $NOT$ exhibit cis-trans isomerism?

Aluminium is extracted from alumina $(Al_2O_3)$ by electrolysis of a molten mixture of:

The obtuse angle between the lines $y = -2$ and $y = x + 2$ is ....$^o$

Let $f$ be a differentiable function such that $f(1)=2$ and $f^{\prime}(x)=f(x)$,for all $x \in \mathbb{R}$. If $h(x)=f(f(x))$,then $h^{\prime}(1)$ is equal to

If $a \cdot \hat{i} = a \cdot (\hat{i} + \hat{j}) = a \cdot (\hat{i} + \hat{j} + \hat{k})$, then $a$ is equal to

If two sides of a triangle are represented by $3x^2-5xy+2y^2=0$ and its orthocentre is $(2,1)$,then the equation of the third side is