Identify elements present in copper pyrites.

The vector equation of a line whose Cartesian equations are $y=2,4 x-3 z+5=0$ is

If 3 books on Physics, 2 books on Chemistry and 4 books on Mathematics are to be arranged on a shelf so that all the Physics books are together and all the Mathematics books are together, then the number of such arrangements is

The value of $\lim _\limits{x \rightarrow 0} \frac{x}{|x|+x^2}$ is