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krek1111 [17]
3 years ago
15

For what values of k

Mathematics
1 answer:
sergey [27]3 years ago
3 0

If y = cos(kt), then its first two derivatives are

y' = -k sin(kt)

y'' = -k² cos(kt)

Substituting y and y'' into 49y'' = -16y gives

-49k² cos(kt) = -15 cos(kt)

⇒   49k² = 15

⇒   k² = 15/49

⇒   k = ±√15/7

Note that both values of k give the same solution y = cos(√15/7 t) since cosine is even.

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(20 points) please give me motivation to study and study tips or test taking tips for finals. it would be greatly appreciated.
Daniel [21]

Answer: Think about graduating. Think about never having to take the courses again. You're almost at the finish line! It'll be worth it. You've worked hard all year for this. You can do it!

Study tips: I would recommend Quizlet! They have a section that generates study games. It's a lot more fun than normal studying. It's also a good idea to make a goal for yourself. Try to make a challenge of achieving a certain score! By the time you accomplish said score, you'll find that you've learned a lot. Another tip is to make sure you take breaks. If you work too long without giving yourself a break, it will become harder to focus and your brain will become tired. Just don't get too distracted! set yourself an alarm during break times to help you stay on task. If you become frustrated with a certain subject or task, take a break from that task. Use this time as an opportunity to work on another subject. You can begin working on the first subject again once you feel refreshed. A lot of this may sound redundant, but hopefully it will help at least a little bit. Good luck!

6 0
3 years ago
Which of the following correctly completes the square for the equation
rjkz [21]

Answer:

A. (x + 2)^2 = 31.

Step-by-step explanation:

x^2 + 4x = 27

x^2 + 4x - 27 = 0

A. (x + 2)^2 = 31

x^2 + 4x + 4 - 31 = 0

x^2 + 4x - 27 = 0

This option corresponds to the given equation, so it is correct.

B. (x + 2)^2 = 43

x^2 + 4x + 4 - 43 = 0

x^2 + 4x - 39 = 0

This does not correspond to the equation.

C. (x + 4)^2 = 31

x^2 + 8x + 16 - 31 = 0

x^2 + 8x - 15 = 0

This does not correspond to the equation.

D. (x+4)^2 = 43

x^2 + 8x + 16 - 43 = 0

x^2 + 8x - 27 = 0

This does not correspond to the equation.

So, your answer is A. (x + 2)^2 = 31.

Make sure to SUBMIT and check your PREVIOUS answers to make sure they are right! XD Also, hope this helps!

7 0
3 years ago
What is the slope intercept form of an equation that goes through (-3,-5) and slope is 3/7
svet-max [94.6K]

Answer:

Step-by-step explanation:

Point slope form: y−7=34(x−3)

Slope intercept form: y=34x+194..or..y=34x+434

Explanation:

Since you have one point and the slope, you can use the point slope formula, then solve for y to get the slope intercept form, so that you can determine the y-intercept (b). Then you can graph the resulting equation.

Point slope formula

y−y1=m(x−x1), where x1,y1=(3,7), and m=34 is the slope.

Substitute the given values into the formula.

7 0
3 years ago
How many solutions does this system have?<br> 7. X = -2
Blizzard [7]

Answer:

One

Explanation:

3

y

=

18

x

+

21

XXX

⇔

y

=

6

x

+

7

5

y

+

55

=

30

x

XXX

⇔

y

=

6

x

−

11

both equations are linear and they are not co-linear

therefore there is exactly 1 solutio

3 0
3 years ago
The right end of this board lines up with the marks halfway between 4 and 5 (Iready) How long is the board?
cupoosta [38]

Answer:

Halfway = 4.5

Step-by-step explanation:

Given

4 and 5

Required

Determine the halfway

This is calculated as:

Halfway = \frac{1}{2}(4 + 5)

Halfway = \frac{1}{2}(9)

Remove bracket

Halfway = \frac{1}{2} * 9

Halfway = 4.5

5 0
3 years ago
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