The points (1,-23) and (6,r) lie on a line with slope 4. Find the missing coordinate r.

F(x) = 2x4 – 17x3 + 35x2 + 9x - 45 can this be factored?

gizmo_the_mogwai [7]

The answer is Yes, you can factor this equation.

5 0

3 years ago

The lateral surface area of cone A is equal to the lateral surface area of cylinder B.

Natasha2012 [34]

Answer:

TRUE

Step-by-step explanation:

Lateral area of cone is given by: πrl

where r is the radius and l is the slant height

Here r=r and l=2h

Hence, lateral area of cone A= π×r×2h

= 2πrh

Lateral area of cylinder is given by: 2πrh

where r is the radius and h is the height

Lateral area of cylinder B=2πrh

Clearly, both the lateral areas are equal

Hence, the statement that:The lateral surface area of cone A is equal to the lateral surface area of cylinder B. is:

True

4 0

3 years ago

The Johnson Farm has 500 acres of land allotted for cultivating corn and wheat. The cost of cultivating corn and wheat (includin

babunello [35]

Answer:

He should plant 100 acres of corn and 400 acres of wheat.

Step-by-step explanation:

This problem can be solved by a siple system of equations.

]x denotes the number of acres of corn

y denotes the number of acres of wheat

Building the system:

The Johnson Farm has 500 acres of land allotted for cultivating corn and wheat. This means that:

$x + y = 500$

The cost of cultivating corn and wheat (including seeds and labor) is $42 and $30 per acre, respectively. Jacob Johnson has $16,200 available for cultivating these crops. This means that:

$42x + 30y = 16,200$

So, we have the following system

$1) x + y = 500$

$2) 42x + 30y = 16,200$

If he wishes to use all the allotted land and his entire budget for cultivating these two crops, how many acres of each crop should he plant?

$1) x + y = 500$

$2) 42x + 30y = 16,200$

I am going to write y as a function of x in 1), and replace in 2). So:

$x + y = 500$ means that $y = 500-x$

$42x + 30y = 16,200$

$42x + 30(500-x) = 16,200$

$42x + 15000 - 30x = 16,200$

$12x = 1,200$

$x = \frac{1,200}{12}$

$x = 100$

Now, going back to 1:

$y = 500 - x = 500 - 100 = 400$

He should plant 100 acres of corn and 400 acres of wheat.

5 0

3 years ago

A metal cylinder can with an open top and closed bottom is to have volume 4 cubic feet. Approximate the dimensions that require

Aleksandr-060686 [28]

Answer:

$r\approx 1.084\ feet$

$h\approx 1.084\ feet$

$\displaystyle A=11.07\ ft^2$

Step-by-step explanation:

Optimizing With Derivatives

The procedure to optimize a function (find its maximum or minimum) consists in :

Produce a function which depends on only one variable
Compute the first derivative and set it equal to 0
Find the values for the variable, called critical points
Compute the second derivative
Evaluate the second derivative in the critical points. If it results positive, the critical point is a minimum, if it's negative, the critical point is a maximum

We know a cylinder has a volume of 4 $ft^3$ . The volume of a cylinder is given by

$\displaystyle V=\pi r^2h$

Equating it to 4

$\displaystyle \pi r^2h=4$

Let's solve for h

$\displaystyle h=\frac{4}{\pi r^2}$

A cylinder with an open-top has only one circle as the shape of the lid and has a lateral area computed as a rectangle of height h and base equal to the length of a circle. Thus, the total area of the material to make the cylinder is

$\displaystyle A=\pi r^2+2\pi rh$

Replacing the formula of h

$\displaystyle A=\pi r^2+2\pi r \left (\frac{4}{\pi r^2}\right )$

Simplifying

$\displaystyle A=\pi r^2+\frac{8}{r}$

We have the function of the area in terms of one variable. Now we compute the first derivative and equal it to zero

$\displaystyle A'=2\pi r-\frac{8}{r^2}=0$

Rearranging

$\displaystyle 2\pi r=\frac{8}{r^2}$

Solving for r

$\displaystyle r^3=\frac{4}{\pi }$

$\displaystyle r=\sqrt[3]{\frac{4}{\pi }}\approx 1.084\ feet$

Computing h

$\displaystyle h=\frac{4}{\pi \ r^2}\approx 1.084\ feet$

We can see the height and the radius are of the same size. We check if the critical point is a maximum or a minimum by computing the second derivative

$\displaystyle A''=2\pi+\frac{16}{r^3}$

We can see it will be always positive regardless of the value of r (assumed positive too), so the critical point is a minimum.

The minimum area is

$\displaystyle A=\pi(1.084)^2+\frac{8}{1.084}$

$\boxed{ A=11.07\ ft^2}$

8 0

3 years ago

A sporting goods store sold 2.5 times as many footballs as basketballs last year. Which statement is true? The ratio of football

Mrac [35]

Footballs : basketballs = 2.5 : 1
(x 2)
footballs : basketballs = 5 : 2
⇒ basketballs : footballs = 2 : 5

Answer: The ratio of basketballs to footballs is 5 : 2.

7 0

3 years ago