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Rom4ik [11]
3 years ago
6

If c varies directly as (r + 1) and c = 8, when r= 3, calculate the value of r when c= 20.

Mathematics
2 answers:
guapka [62]3 years ago
8 0

c = k(r + 1)

8 = k(3 + 1)

8 = 4k

8/4 = k

2 = k

c=2(r + 1)

When c = 20, then

20 = 2(r + 1)

20 = 2r + 2

20 - 2 = 2r

18 = 2r

18/2 = r

9 = r

Therefore, the value of r is 9 when c is 20..

Aneli [31]3 years ago
5 0

Answer:

r = 9

Step-by-step explanation:

Given that c varies directly as (r + 1) then the equation relating them is

c = k(r + 1) ← k is the constant of variation

To find k use the condition c = 8 when r = 3, then

8 = k(3 + 1) = 4k ( divide both sides by 4 )

2 = k

c = 2(r + 1) ← equation of variation

When c = 20, then

20 = 2(r + 1) ← divide both sides by 2

10 = r + 1 ( subtract 1 from both sides )

9 = r

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3 years ago
The graphs of the function f (given in blue) and g (given in red) are plotted above. Suppose that u(x)=f(x)g(x) and v(x)=f(x)/g(
Rus_ich [418]
U(x) = f(x).(gx)
v(x) = f(x) /  g(x)

Use chain rule to find u(x) and v(x).

u '(x) = f '(x) g(x) + f(x) g'(x)

v ' (x) = [f '(x) g(x) - f(x) g(x)] / [g(x)]^2

The functions given are piecewise.

You need to use the pieces that include the point x = 1.

You can calculate f '(x) and g '(x) at x =1, as the slopes of the lines that define each function.

And the slopes can be calculated graphycally as run / rise of each graph, around the given point.

f '(x) = slope of f (x); at x = 1, f '(1) = run / rise = 1/1 = 1

g '(x) = slope of g(x); at x = 1, g '(1) = run / rise = 1.5/ 1 = 1.5

You also need f (1) = 1 and g(1) = 2

Then:

u '(1) =  f '(1) g(1) + f(1) g'(1) = 1*2 + 1*1.5 = 2 + 1.5 = 3.5

v ' (x) = [f '(1) g(1) - f(1) g(1)] / [g(1)]^2 = [1*2 -  1*1.5] / (2)^2 = [2-1.5]/4 =

= 0.5/4 = 0.125

Answers:
u '(1) = 3.5
v '(1) = 0.125

 


 

3 0
3 years ago
The accompanying data resulted from an experiment in which weld diameter x and shear strength y (in pounds) were determined for
saul85 [17]

Answer:

y hat = 2114.20 + 18.96x

Step-by-step explanation:

Given the least square regression model equation:

y hat = -959.00 + 8.60x

weld diameter x ; shear strength y (in pounds)

1 lb = 0.4536 kg

To express shear strength y in kilogram:

y is multiplied by 0.4536

(y hat × 0.4536) = -959.00 + 8.60x

Divide both sides by 0.4536

(y hat × 0.4536) / 0.4536= (-959.00 + 8.60x) / 0.4536

y hat = 2114.1975 + 18.959435x

y hat = 2114.20 + 18.96x

7 0
3 years ago
A coin and a die is rolled. What is the probability of a head and a 3?
saw5 [17]

Answer:

1/6

Step-by-step explanation:

The probability of <em>only</em> a heads on a coin is 1/2, and the probability of <em>only</em> a 3 on a die is 1/6. Multiply them together, and you get 1/6.

6 0
3 years ago
HELP ME PLEASE HELP ME HELP ME PLEASE
riadik2000 [5.3K]

Answer:

<h2>     no, because the remainder is 126</h2>

Step-by-step explanation:

if x+3 is a factor, then -3 is a root of expression, and the remainder would be 0

calculating remainder:

-3(-3)^3+6(-3)^2+6(-3)+9=-3\cdot(-27)+6\cdot9-18+9=\\\\=81+54-9=126

4 0
4 years ago
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