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dusya [7]
3 years ago
8

which of the following is a solution of 2cos^2x-cost-1=0 a. 0 degrees b. 150 degrees c. 180 degrees d. 210 degrees

Mathematics
1 answer:
Luba_88 [7]3 years ago
3 0

Answer:

{0, 150} degrees

Step-by-step explanation:

Given 2cos^2x-cost-1=0, let's simplify this problem by temporarily replacing cos x with y:

2y^2 - y -1 = 0

This can be solved by factoring:  (2y + 1)(y - 1) = 0.  From this we get two solutions:  y = -1/2 and y = 1.

Remembering that we let y = cos x, we now solve:

cos x = -1/2 and cos x = 1.

Note that cos x = 1 when x = 0 and the "adjacent side" coincides with the hypotenuse.

cos x = -1/2 when the hypotenuse is 2 and the "adjacent side" is -1.  This has two solutions between 0 and 360 degrees:  150 degrees and  270 degrees.

Four answer choices are given.  Both (a) (0 degrees) and (b) (150 degrees) satisfy the original equation.  Thus, the solution set is {0, 150} (degrees).

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$98.30=5.1a+11.6
98.30-11.6=5a+11.6-11.6
86.7=5a
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17.34=a
So only 17 people can attend

5 0
4 years ago
(-3+-2^2) + -(4*2) / 2
ozzi

Answer:

-3

Step-by-step explanation:

2^2 = 4

4 + (-3) = 1

4*2 = 8

8 * -1 = -8

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1 + -4 = -3

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3 years ago
On a trip to visit friends, a family drives 65 miles per hour for 208 miles of the trip. If the entire trip was 348 miles and to
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From information given, we know
208 miles was at rate of 65 mph. so divide total mileage by speed to get time spent.

208 ÷ 65 = 3.2 hours

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4 0
3 years ago
Amy and her three friends love to eat pizza for lunch. Amy's mother bakes
HACTEHA [7]

Amy has a fraction of 2/3

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_______________________

Jill and Lila both at the same amount of pizza.

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4 years ago
When the outliers are removed, how does the mean change? (2 points) dot plot with 1 on 50, 1 on 76, 1 on 78, 2 on 79, 1 on 80, 1
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Answer:

Answer: The mean increases by 3

Step-by-step explanation:

The original data set is 

{50, 76, 78, 79, 79, 80, 81, 82, 82, 83}

The outlier is 50 because it is not near the group of values from 76 to 83 which is where the main cluster is.

The original mean is M = (50+76+78+79+79+80+81+82+82+83)/10 = 77

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So that's why the mean increases by 3

8 0
3 years ago
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