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2 years ago

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What is the sum of the infinite geometric series? Sigma-Summation Underscript n = 1 Overscript 4 EndScripts (negative 144) (one-

half) Superscript n minus 1

2 answers:

11Alexandr11 [23.1K]2 years ago

8 0

Step-by-step explanation:

∑⁴ₙ₌₁ -144 (½)ⁿ⁻¹

This is a finite geometric series with n = 4, a₁ = -144, and r = ½.

S = a₁ (1 − rⁿ) / (1 − r)

S = -144 (1 − (½)⁴) / (1 − ½)

S = -270

If you wanted to find the infinite sum (n = ∞):

S = a₁ / (1 − r)

S = -144 / (1 − ½)

S = -288

VLD [36.1K]2 years ago

4 0

Answer:

The answer is C (40)

Step-by-step explanation:

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Your utility company charges 13 cents per kilowatt-hour of electricity. What is the daily cost of keeping lit a 75 watt light bu

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we know that

$1 Kw=1000 w$

The company charges $13$ cents per kilowatt-hour of electricity

$13 cents=0.13 dollars\\\\ 75w=\frac{75}{1000} kw\\\\ 15w=\frac{15}{1000} kw$

Step $1$

Find the cost for the light bulb

a) in one day

$\frac{75}{1000} *12=0.9\ kw\ hour$

$Cost=0.13*0.9$

Cost=$ $0.117$

b) In a year

$\frac{75}{1000} *12=0.9\ kw\ hour$

$0.9*365=328.5\ kw\ hour$

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Cost=$ $42.71$

Step $2$

Find the cost for the led bulb

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$\frac{15}{1000} *12=0.18\ kw\ hour$

$Cost=0.13*0.18$

Cost=$ $0.0234$

b) In a year

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$0.18*365=65.7\ kw\ hour$

$Cost=0.13*65.7$

Cost=$ $8.54$

Step $3$

Find the difference in cost

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therefore

the answer is

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2 years ago

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I belive the correct answer would be 300 mp/h

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2 years ago

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An experienced carpenter can frame a house twice as fast as an apprentice. Working together, it takes the carpenters 2 days. How

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Answer:

<em>6 days</em>

<em></em>

Step-by-step explanation:

Let the time taken by Carpenter working alone = $C$ days

Then time taken by apprentice alone = Twice as that of taken by Carpenter = 2 $C$ days

Time taken working together = 2 days

Work done in one day working together = $\frac{1}{2}$

Work done in one day by Carpenter working alone = $\frac{1}{C}$

Work done in one day by apprentice working alone = $\frac{1}{2C}$

Work done in one day by Carpenter working alone + Work done in one day by Carpenter working alone = $\frac{1}{C}$ + $\frac{1}{2C}$ = Work done in one day working together = $\frac{1}{2}$

$\dfrac{1}{C}+\dfrac{1}{2C}=\dfrac{1}{2}\\\Rightarrow \dfrac{2+1}{2C}=\dfrac{1}{2}\\\Rightarrow C = 3\ days$

Time taken by Carpenter alone to complete the work = 3 days

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2 years ago

Your friend is trying to grow her hair as long as her cousin’s hair. The table shows their hair lengths y (in inches) in differe

Effectus [21]

<span>Given the table that shows the hair lengths y (in inches) of your friend and her cousin in different months x.

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To solve for the cousins hair, recall that the equation of a line is given by

y = mx + c

From the table,

7 = 3m + c . . . (1)
9 = 8m + c . . . (2)

(1) - (2) ⇒ -2 = -5m
$\Rightarrow m= \frac{2}{5} =0.4$

Substituting for m into equation (1) gives:

$7=3(0.4)+c \\ \\ \Rightarrow c=7-1.2=5.8$

Therefore, the equation representing the growth of the cousin's hair is given by y = 1.2x + 5.8
</span>

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rodikova [14]

Answer:

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