The graph represents distance traveled varying directly with time.

Mathematics

2 answers:

AnnZ [28]2 years ago

4 0

YOUR ANSWER WILL BE C- HOPE THIS HELPED!!

irinina [24]2 years ago

3 0

The direct variation equation is $\frac{y}{x}=k$ . That means, in words, that y varies directly as x. k is the constant of variation. We can pick a coordinate point on the graph to solve for this constant, then use that constant along with the x value of 9 hours to find the distance we could travel in that 9 hours. This is kind of like a way to write a linear equation that you could use as a model. I picked the point (2.5, 100) since the line goes right through that point. Fitting those points into the direct variation equation we get $\frac{100}{2.5}=k$ . If we solve for k we get that k = 40. Now since time is an x value and distance is a y value, we are looking to solve for y when x = 9. We have the k, so here's the equation: $\frac{y}{9}=40$ . We multiply both sides by 9 to solve for y. y = 360. Choice b from above. There you go!

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Hi! I need help with the attached question in calc. Thank you:)

Elena L [17]

Answer:

3π square units.

Step-by-step explanation:

We can use the disk method.

Since we are revolving around AB, we have a vertical axis of revolution.

So, our representative rectangle will be horizontal.

R₁ is bounded by y = 9x.

So, x = y/9.

Our radius since our axis is AB will be 1 - x or 1 - y/9.

And we are integrating from y = 0 to y = 9.

By the disk method (for a vertical axis of revolution):

$\displaystyle V=\pi \int_a^b [R(y)]^2\, dy$

So:

$\displaystyle V=\pi\int_0^9\Big(1-\frac{y}{9}\Big)^2\, dy$

Simplify:

$\displaystyle V=\pi\int_0^9(1-\frac{2y}{9}+\frac{y^2}{81})\, dy$

Integrate:

$\displaystyle V=\pi\Big[y-\frac{1}{9}y^2+\frac{1}{243}y^3\Big|_0^9\Big]$

Evaluate (I ignored the 0):

$\displaystyle V=\pi[9-\frac{1}{9}(9)^2+\frac{1}{243}(9^3)]=3\pi$

The volume of the solid is 3π square units.

Note:

You can do this without calculus. Notice that R₁ revolved around AB is simply a right cone with radius 1 and height 9. Then by the volume for a cone formula:

$\displaystyle V=\frac{1}{3}\pi(1)^2(9)=3\pi$