$\"\"$

The demand function is $\"\"$ .

When the sales level is $\"\"$ , the price is $\"\"$ .

From definition 1:

The surplus is $\"\"$ .

$\"\"$

$\"\"$ .

The consumer surplus is $\"\"$ .

$\"\"$

Graph:

Graph the function $\"\"$ .

$\"\"$

Observe the Graph:

The consumer surplus is in the shape of triangle.

The area of triangle is $\"\"$ .

The consumer surplus is $\"\"$ .

$\"\"$

The consumer surplus is $\"\"$ .