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butalik [34]
3 years ago
15

If sin theta = 1/3 and tan theta < 0, what is the value of cos theta?

Mathematics
1 answer:
STatiana [176]3 years ago
5 0
If sin Ф=1/3>0 and tan Ф<0; then Ф belongs to the second quadrant and cos Ф will be negative (cos Ф<0).

sin²Ф+cos²Ф=1
(1/3)²+cos²Ф=1
1/9+cos²Ф=1
cos²Ф=1-1/9
cos²Ф=8/9
cos Ф=⁺₋√(8/9)=⁺₋2√2 / 3

We have two possible solutions.
cos Ф=2√2 / 3 This solutions is not possible, because in this case cos Ф has to be negative (cos Ф<0)

cos Ф=(-2√2) / 3 this solutions is right.

answer:B. -2 square root 2 /3    (or    (-2√2) /3  )
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Jesse is sanding a circular wooden table that has a diameter of 6 ft. She can sand 5 square feet every hour. At this rate, appro
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The time it will take Jesse to finish sanding the table is approximately 22.61 hours.

<h3>How to find the area of a circle?</h3>

Suppose the circle has radius of 'r' units, then, its area is given as:

A  = \pi \times (r)^2 sq. units

Since radius of a circle is half of its diameter, so if diameter is of 'd' length, then r= d/2, thus, area can be rewritten as:

A = \pi \times (\dfrac{d}{2})^2 sq. units

For the given case, sanding being done needs to be equal to the area of the circular table, as it has to be done for whole table's surface, which is circular, and area of sanding done will be equal to the area of that circular table.

The area of table(diameter given as 6 ft) is: A = \pi \times (\dfrac{d}{2})^2 \approx 3.14 \times 6^2 = 113.04 \: \rm ft^2

Since Jesse does 5 sq. feet per hour, let she takes T hours time to finish sanding the table, then we have:

\rm T \times 5\:  ft^2 = A \approx 113.04 \: ft^2\\\\\text{Dividing all sides by 5, we get}\\\\T = \dfrac{113.04}{5} \approx 22.61 \: hours

(since 5 sq. feet in 1 hours, then in T hours, T times 5 sq. feet will be done which is equal to area of table, as in approx T hours, she finishes sanding the table)

Thus, it will take approx 22.61 hours for Jesse to finish sanding the table.

Learn more about area of circle here:

brainly.com/question/13056790

8 0
2 years ago
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Answer:

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Step-by-step explanation:

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8 0
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Answer:

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8 + 3x = 29 + 2x

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3 0
2 years ago
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