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3 years ago

What is 1/35 X 15?isn't it 3/7?

Mathematics

1 answer:

sp2606 [1]3 years ago

7 0

1/35 x 15 is 0.428571<span>
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PLEASE HELP ASAP In this task, you will practice finding the area under a nonlinear function by using rectangles. You will use g

mrs_skeptik [129]

Answer:

a) $1280 u^{2}$

b) $1320 u^{2}$

c) $\frac{4000}{3} u^{2}$

Step-by-step explanation:

In order to solve this problem we must start by sketching the graph of the function. This will help us visualize the problem better. (See attached picture)

You can sketch the graph of the function by plotting as many points as you can from x=0 to x=20 or by finding the vertex form of the quadratic equation by completing the square. You can also do so by using a graphing device, you decide which method suits better for you.

So we are interested in finding the area under the curve, so we divide it into 5 rectangles taking a right hand approximation. This is, the right upper corner of each rectangle will touch the graph. (see attached picture).

In order to figure the width of each rectangle we can use the following formula:

$\Delta x=\frac{b-a}{n}$

in this case a=0, b=20 and n=5 so we get:

$\Delta x=\frac{20-0}{5}=\frac{20}{5}=4$

so each rectangle must have a width of 4 units.

We can now calculate the hight of each rectangle. So we figure the y-value of each corner of the rectangles. We get the following heights:

h1=64

h2=96

h3=96

h4= 64

h5=0

so now we can use the following formula to find the area under the graph. Basically what the formula does is add the areas of the rectangles:

$A=\sum^{n}_{i=1} f(x_{i}) \Delta x$

which can be rewritten as:

$A=\Delta x \sum^{n}_{i=1} f(x_{i})$

So we go ahead and solve it:

$A=(4)(64+96+96+64+0)$

so:

$A= 1280 u^{2}$

B) The same procedure is used to solve part B, just that this time we divide the area in 10 rectangles.

In order to figure the width of each rectangle we can use the following formula:

$\Delta x=\frac{b-a}{n}$

in this case a=0, b=20 and n=10 so we get:

$\Delta x=\frac{20-0}{10}=\frac{20}{10}=2$

so each rectangle must have a width of 2 units.

We can now calculate the hight of each rectangle. So we figure the y-value of each corner of the rectangles. We get the following heights:

h1=36

h2=64

h3=84

h4= 96

h5=100

h6=96

h7=84

h8=64

h9=36

h10=0

so now we can use the following formula to find the area under the graph. Basically what the formula does is add the areas of the rectangles:

$A=\sum^{n}_{i=1} f(x_{i}) \Delta x$

which can be rewritten as:

$A=\Delta x \sum^{n}_{i=1} f(x_{i})$

So we go ahead and solve it:

$A=(2)(36+64+84+96+100+96+84+64+36+0)$

so:

$A= 1320 u^{2}$

In order to find part c, we calculate the area by using limits, the limit will look like this:

$\lim_{n \to \infty} \sum^{n}_{i=1} f(x^{*}_{i}) \Delta x$

so we start by finding the change of x so we get:

$\Delta x =\frac{b-a}{n}$

$\Delta x =\frac{20-0}{n}$

$\Delta x =\frac{20}{n}$

next we find $x^{*}_{i}$

$x^{*}_{i}=a+\Delta x i$

so:

$x^{*}_{i}=0+\frac{20}{n} i=\frac{20}{n} i$

and we find $f(x^{*}_{i})$

$f(x^{*}_{i})=f(\frac{20}{n} i)=-(\frac{20}{n} i)^{2}+20(\frac{20}{n} i)$

cand we do some algebra to simplify it.

$f(x^{*}_{i})=-\frac{400}{n^{2}}i^{2}+\frac{400}{n}i$

we do some factorization:

$f(x^{*}_{i})=-\frac{400}{n}(\frac{i^{2}}{n}-i)$

and plug it into our formula:

$\lim_{n \to \infty} \sum^{n}_{i=1}-\frac{400}{n}(\frac{i^{2}}{n}-i) (\frac{20}{n})$

And simplify:

$\lim_{n \to \infty} \sum^{n}_{i=1}-\frac{8000}{n^{2}}(\frac{i^{2}}{n}-i)$

$\lim_{n \to \infty} -\frac{8000}{n^{2}} \sum^{n}_{i=1}(\frac{i^{2}}{n}-i)$

And now we use summation formulas:

$\lim_{n \to \infty} -\frac{8000}{n^{2}} (\frac{n(n+1)(2n+1)}{6n}-\frac{n(n+1)}{2})$

$\lim_{n \to \infty} -\frac{8000}{n^{2}} (\frac{2n^{2}+3n+1}{6}-\frac{n^{2}}{2}-\frac{n}{2})$

and simplify:

$\lim_{n \to \infty} -\frac{8000}{n^{2}} (-\frac{n^{2}}{6}+\frac{1}{6})$

$\lim_{n \to \infty} \frac{4000}{3}+\frac{4000}{3n^{2}}$

and solve the limit

$\frac{4000}{3}u^{2}$

4 0

3 years ago

A rectangle has a length of (x + 4) inches and a width of (x) inches. If the area of the rectangle is 192 inches squared, what i

Anestetic [448]

Answer:34

Step-by-step explanation:

3 0

3 years ago

Simplify the following expression, show all work you did to get the results

777dan777 [17]

Answer:

(sqrt(7))/3 or decimal 0.8819171036881968635005385845464201419034197276941500601227781530...

Step-by-step explanation:

Simplify the following:

(sqrt(14))/(sqrt(18))

Hint: | Simplify radicals.

sqrt(18) = sqrt(2×3^2) = 3 sqrt(2):

(sqrt(14))/(3 sqrt(2))

Hint: | Multiply numerator and denominator of (sqrt(14))/(3 sqrt(2)) by sqrt(2).

Rationalize the denominator. (sqrt(14))/(3 sqrt(2)) = (sqrt(14))/(3 sqrt(2))×(sqrt(2))/(sqrt(2)) = (sqrt(14) sqrt(2))/(3×2):

(sqrt(14) sqrt(2))/(3×2)

Hint: | Multiply 3 and 2 together.

3×2 = 6:

(sqrt(14) sqrt(2))/6

Hint: | For a>=0, sqrt(a) sqrt(b) = sqrt(a b). Apply this to sqrt(14) sqrt(2).

sqrt(14) sqrt(2) = sqrt(14×2):

(sqrt(14×2))/6

Hint: | Multiply 14 and 2 together.

14×2 = 28:

(sqrt(28))/6

Hint: | Simplify radicals.

sqrt(28) = sqrt(2^2×7) = 2 sqrt(7):

(2 sqrt(7))/6

Hint: | In (2 sqrt(7))/6, divide 6 in the denominator by 2 in the numerator.

2/6 = 2/(2×3) = 1/3:

Answer: (sqrt(7))/3

5 0

3 years ago

In the triangle below, what is the side opposite the 30 degree angle

Afina-wow [57]

$tan(30^o)= \frac{opposite }{adjacent} \ \ \ \ \to \\ \\ opposite = adjacent*tan(30^o)=3* \frac{ \sqrt{3} }{3} = \sqrt{3}$

4 0

3 years ago

Someone help? Plz I will give u more points

Rina8888 [55]

Answer:

4.255 ft²

Step-by-step explanation:

the area of the figure =

(2.25 × 1.5)+(1/8 ×3.14× 1.5²)

= 3.375 + 0.88

= 4.255 ft²

6 0

2 years ago