For each <em>x</em> in the interval 0 ≤ <em>x</em> ≤ 5, the shell at that point has
• radius = 5 - <em>x</em>, which is the distance from <em>x</em> to <em>x</em> = 5
• height = <em>x</em> ² + 2
• thickness = d<em>x</em>
and hence contributes a volume of 2<em>π</em> (5 - <em>x</em>) (<em>x</em> ² + 2) d<em>x</em>.
Taking infinitely many of these shells and summing their volumes (i.e. integrating) gives the volume of the region:
Answer:
The third picture
Step-by-step explanation:
Solve for x in both equations
2x<6
Divide both sides by 2:
x<3
3x+2>-4
Subtract 2 from both sides:
3x>-6
Divide both sides by 3:
x>-2
There is this trick you can use when x is on the left side of the equation to find out which way to shade in you graph. Keep in mind this is only for the left side, it will not work if your variable is on the right.
When the symbol is facing left < then shade left, imagine it is pointing which way to shade. x<3 is represented by the 3 picture on the left. When the symbol is facing right > then shade right, again it is pointing which way to shade. x>-2 is represented by the 3 picture on the right.
The circles are not filled in because the symbol is < and > rather than . When it is greater than or equal to or less than and equal to (represented by the line under the symbol), then the circle is shaded in.