1. The problem involves understanding the graphs described and their equations. 2. We are given two lines related to a variable $x$ and a parameter $\beta t.i-1$: - The first line is along the x-axis, represented by the equation $y=0x$, which simplifies to $y=0$. This means the line coincides with the x-axis. 3. The second line is given by $y=xt$, indicating that for each $x$, the value of $y$ is $x$ multiplied by some factor $t$. This describes a line passing through the origin with slope $t$. 4. An angle $\theta$ is marked between the line $y=xt$ and the x-axis. 5. The arrow labeled $(\beta t.i-1)$ on the y-axis indicates a vertical shift or parameter related to the problem but no explicit function is provided to incorporate this. 6. The domain or ensemble de d\'efinition (set of definition) for $x$ is given from 0 to 5, consistent with the graph description. 7. Summary: - Line 1: $y=0$ (x-axis) - Line 2: $y=tx$ (line through origin with slope $t$) - Angle $\theta$ between these lines - $x$ defined on $[0,5]$ Final answer: The problem describes two linear functions $y=0$ and $y=tx$ over the domain $0 \leq x \leq 5$, with an angle $\theta$ between them and a parameter $(\beta t.i-1)$ possibly related to the vertical axis or a transformation.