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melomori [17]
3 years ago
7

Math Q 8

Mathematics
1 answer:
Blababa [14]3 years ago
4 0
If you have to do 70% of your projects and you have 3, you can approach this problem by showing that each project is 33.3% (I did 100/3 to determine what percentage each project is worth). 

If we do one project, 33.3% is completed
If we do two projects, 66.6% is completed
If we do three projects, 100% is completed

Since we have to do at least 70%, we must do all three projects.
You might be interested in
Solve the differential equation by variation of parameters.<br><br> y''+y=secx
suter [353]

Answer:y=

Acosx+Bsinx +cosx ln(cosx)+x sinx

Step-by-step explanation:

given  equation y''+y=secx

auxiliary  equation

p^2+1=0\\p=\pm i

so CF is y=Acosx+Bsinx

now

y_1(x)=cosx \ \ \ \ y_2(x)=sinx\\{y_1}'(x)=-sinx \ \ \ \ {y_2}'(x)=cosx

using wronskian formula

W=\begin{vmatrix}cosx &sinx \\ -sinx & cosx\end{vmatrix}

          =cos^2x+sin^2x=1

now f(x)=secx

u=-\int \frac{f(x)y_2(x)}{W(x)}dx \ and \ v=\int \frac{f(x)y_1(x)}{W(x)}dx

u=-\int \frac{secx\times sinx}{1}dx \ and \ v=\int \frac{secx\times cosx}{1}dx

u=-\int tanx dx \ and \ v=\int {1}dx

u=ln(cosx) \ \ \ and \ \ v=x

now particular integrals are

PI=cosx ln(cosx)+x sinx

total solution

y= C.F+P.I

y=Acosx+Bsinx +cosx ln(cosx)+x sinx

8 0
4 years ago
The shadow of a tree measures 25 feet from its base. The angle of elevation to the Sun is 31º How tall is the tree? Round your a
grigory [225]

Answer: 15 feet

Step-by-step explanation:

Hi, since the situation forms a right triangle (see attachment) we have to apply the next trigonometric function.  

Tan α = opposite side / adjacent side

Where α is the angle of elevation to the sun, , the opposite side (x) is the height of the tree, and the adjacent side is the length of the shadow.

Replacing with the values given:  

Tan 31 = x /25

Tan 31 (25) =x

x = 15 feet

Feel free to ask for more if needed or if you did not understand something.  

4 0
4 years ago
9x9=<br> 8x8=<br> 8x7=<br> 5x4=<br> Vă rog să mă ajutați
sergiy2304 [10]

Answer:

9×9=72

8×8=64

8×7=56

5×4=20

4 0
3 years ago
Read 2 more answers
The scores on a test for a sample of 42 statistics students are summarized in the following table. 9, 90, 18, 80, 15, 70. Find t
igomit [66]
<h3>Answer:   78.6</h3>

Work Shown:

\begin{array}{|c|c|} \cline{1-2}\text{Number of People} & \text{Score}\\\cline{1-2}9 & 90\\\cline{1-2}18 & 80\\\cline{1-2}15 & 70\\\cline{1-2}\end{array}

Multiply across the rows to form a third column. Example: 9*90 = 810 in the first row.

\begin{array}{|c|c|c|} \cline{1-3}\text{Number of People} & \text{Score} & \text{Number*Score}\\\cline{1-3}9 & 90 & 810\\\cline{1-3}18 & 80 & 1440\\\cline{1-3}15 & 70 & 1050\\\cline{1-3}\end{array}

The values in the third column add to 810+1440+1050 = 3300

Divide this over the total number of people which is 9+18+15 = 42

The mean is 3300/42 =78.571 approximately which rounds to 78.6

5 0
2 years ago
Someone help, I suck at math
attashe74 [19]

option A.55°

Answer:

Solution given:

<x+<y=<z

exterior angle of a triangle is equal to the sum of two opposite interior angle

4n-18+n+8=133-6n

5n+6n=133+10

11n=143

n=143/11

n=13

<u>exterior</u><u> </u><u>angle</u><u> </u><u>=</u><u>1</u><u>3</u><u>3</u><u>-</u><u>6</u><u>*</u><u>1</u><u>3</u><u>=</u><u>5</u><u>5</u><u>°</u>

<u>option</u><u> </u><u>A</u><u>.</u><u>5</u><u>5</u><u>°</u>

5 0
3 years ago
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