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3 years ago

11

A sample of 7 students was taken to see how many pencils they were carrying 2,3,2,5,7,1,4 calculate the standard deviation

1 answer:

Firdavs [7]3 years ago

6 0

Answer:

1.92

Step-by-step explanation:

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All acute triangles are similar. <br> a. True<br> b. False

nirvana33 [79]

Kind of true and kind of false : Sometimes they are, but there is nothing that force two acture triangles to be similar, even if they have the same measurement of the acute angle.

For that you would need to have 3 angles the same.

For example, if the angles were 40-60-80, you have an acute triangle. But if you had a 45-55-80 triangle, that is also acute, but not similar even though it shares an angle of 80 degrees.

8 0

2 years ago

Read 2 more answers

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

3 years ago

Which of the following is NOT true about unit rates?

lisov135 [29]

A, it’s the move for that wuestion

3 0

2 years ago

I'd really appreciate it if anyone helped! :) Giving Brainliest!

Anna11 [10]

the first three are irrational

5 0

2 years ago

Given that 3x-y : x+2y = 2 : 5, Determine the ratio x:y

N76 [4]

Answer:

x : y = 9 : 13

Step-by-step explanation:

Given that

3x - y : x + 2y = 2 : 5

Express the ratio in fractional form, that is

$\frac{3x-y}{x+2y}$ = $\frac{2}{5}$ ( cross- multiply )

5(3x - y) = 2(x + 2y) ← distribute parenthesis on both sides )

15x - 5y = 2x + 4y ( subtract 2x from both sides )

13x - 5y = 4y ( add 5y to both sides )

13x = 9y ( divide both sides by 13 )

x = $\frac{9}{13}$ y ( divide both sides by y )

$\frac{x}{y}$ = $\frac{9}{13}$ , that is

x : y = 9 : 13

7 0

3 years ago