general question about finding area of a solid by rotating axis

[KataKoniK]

I just have a general question here. There's this question in the textbook that asks to sketch a graph and then find the volume generated by revolving the region about the x-axis. The three equations they give is y = x, y = 0, x = 1.

Aren't we suppose to sketch a graph of those three equations? Because in the sols manual, they graph instead, y = x^3 and x + y = 10

[hypermorphism]

I just have a general question here. There's this question in the textbook that asks to sketch a graph and then find the volume generated by revolving the region about the x-axis. The three equations they give is y = x, y = 0, x = 1.

Aren't we suppose to sketch a graph of those three equations? Because in the sols manual, they graph instead, y = x^3 and x + y = 10
The solutions manual may be for a different edition, because there is no reason to graph the two equations it contains with respect to the original question.

[KataKoniK]

Thanks. I thought there was some mathematical reasoning behind graphing those two equations in the manual.

[dextercioby]

I just have a general question here. There's this question in the textbook that asks to sketch a graph and then find the volume generated by revolving the region about the x-axis. The three equations they give is y = x, y = 0, x = 1.

Aren't we suppose to sketch a graph of those three equations? Because in the sols manual, they graph instead, y = x^3 and x + y = 10

Nevermind the solution.In the original form,the text doesn't make any sense...The volumes considered are either 0 or infinite...

Daniel.

[KataKoniK]

Thanks Dan

[hypermorphism]

Nevermind the solution.In the original form,the text doesn't make any sense...The volumes considered are either 0 or infinite...

Daniel.

Hi dexter,
I believe the text is talking about rotating the area contained by those 3 equations, which is a right-triangle with a vertex at the origin.

[Galileo]

Hi dexter,
I believe the text is talking about rotating the area contained by those 3 equations, which is a right-triangle with a vertex at the origin.
Indeed, by rotating the region bounded by the three graphs you get a cone of height 1 and radius 1.