[Math] Determine the region bounded by the inequalities

inequality

Determine the region bounded by the inequalities:
$$
0 \leq x + y \leq 1 \\
0 \leq x – y \leq x + y
$$

I don't know what to solve for first, so I just added them:

$$
0 \leq x \leq 1 + x + y \\
$$

I guess I can subtract $x$:

$$
-x \leq 0 \leq 1 + y \\
$$

Or:

$$
-y – 1 \leq 0 \leq x \\
$$

So from this inequality, it looks like some area in the 4th quadrant because $x \geq 0$ means everything to the right of the $y$-axis, and $-y – 1 \leq 0$ means $- 1 \leq y$ which is above the line $y = -1$. However, it looks like I'm analyzing incorrectly as the answer says that it is some area above $y = 0$. I'm not sure what I'm doing wrong.

Best Answer

The inequalities are: $$y\le 1-x$$ $$y\ge -x$$ $$y\ge 0$$ $$y\le x$$ You should graph these and determine the region where all the inequalities hold. Here is a picture of what it should look like

enter image description here

Related Question