Area of the region bounded by curve $y^2=4 x$ and the $X$-axis between $x=0$ and $x=1$ is

The order of the differential equation $\frac{d^4 y}{d x^4}-\sin \left(\frac{d^2 y}{d x^2}\right)=5$

The position vectors of points P and Q are $\vec{p}$ and $\vec{q}$ respectively. The point $R$ divides line segment $P Q$ in the ratio $3: 1$ and S is the mid-point of line segment PR. The position vector of $S$ is

The angle which the line $\frac{x}{1}=\frac{y}{-1}=\frac{z}{0}$ makes with the positive direction of Y -axis is