Find the zeros of the function in the interval. [-2π, 2π]

The zeroes of the f(x) = ± π/4 , ±3π/4 , ±5π/4 , ±7π/4 ⇒ answer (d)

Step-by-step explanation:

* The domain of the function f(x) = 1/2 cos(2x) is [-2π , 2π]

* That means -2π ≤ x ≤ 2π

∴ The domain of 2x is ⇒ -4π ≤ 2x ≤ 4π

* lets solve for 2x and then find the values of x

∵ f(x) = 1/2 cos(2x)

∴ The zeroes of the function means f(x) = 0

∴ 1/2 cos(2x)  = 0 ⇒ multiply both sides by 2

∴ cos(2x) = 0

* In the four quadrant the values of cosФ = 0 at the y-axis with angles

  π/2 , 3π/2 (anti-clockwise) , -π/2 , -3π/2 (clockwise) for 1 cycle,

  but we have 2 cycles for 2x, so we add 2π for every angle of

  2x, then we have other 4 angles 5π/2 , 7π/2 (anti-clockwise),

  -5π/2 , -7π/2 (clockwise)

∴ 2x = ± π/2 , ±3π/2 , ±5π/2 , ±7π/2

* To find the value of x divide all by 2

∴ x = ± π/4 , ±3π/4 , ±5π/4 , ±7π/4

* The zeroes of the f(x) = ± π/4 , ±3π/4 , ±5π/4 , ±7π/4

answer:

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payment for service including tax

→

$

94.09

explanation:

service only with 20% tip  

→

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1

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$

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in the opening of the question the word 'service' is associated only with the pretax value.

the closing part of the question asks: how much did she pay for the  

service

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so technically the answer is  

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$

72.6

(

1

+

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$

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however, the intention of the question provider may have been that your answer is to be  

$

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$

94.09

to 2 decimal places.

'

payment just for service  

→

$

87.12

payment for service including tax

→

$

94.09

tony b

mar 21, 2017

answer:

trying to explain it another way

explanation:

service charge  

.

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$

72.60

20% tip  

20

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8

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$

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$

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related questions

step-by-step explanation:

descending order means to order the polynomials from the term with the largest exponent to the term with the smallest exponent.  

therefore, the correct answer is d.