# write

1. ### How to write imaginary numbers

Hi, I have a question to solve: y''+4y'+25y=0. Substituting theta e^theta(x) - led to theta = -4+or-(sqrt -84_/2 (ie 4 plus or minus sqrt -84 all divided by two). This leaves two imaginary numbers generated by taking sqrt of -84: To write these do I write e^i-4+(etc rest of quad form) and...
2. ### Write equation and solve. Show work.

At precisely noon, one plane leaves New York, heading for Orlando, and another leaves Orlando, heading for New York. The distance is 1300 mi. The plane from New York flies at 450 mph and the Orlando plane flies at 490 mph. When will planes be 125 mi apart. Here's what I have: 450(t) +...
3. ### How to write Matlab code for this PDE problem?

Hello, so I have this problem and I did not receive full credit on it and I would love to have the correct answer for future problems. I attached an image of the problem and what I had and I could never get my code to run so any help is appreciated. Thanks! dx = 1e-2; dt = 1e-5; u(x,0) =...
4. ### How to write decimals as simple fractions (and other way round.)

Can you just explain 'how to' turn decimals into fractions and fractions into decimals?(Itwasntme)
5. ### Show that S is a basis for T, and write down the dimension of T.

Regarding the two subsets of R4: S = {(1, 1, 0, −1), (1, −2, 1, 6), (1, 1, 1, 0)}, T = {(x, y, z, x − 2y + z) : x, y, z ∈ R}. Show that S is a basis for T, and write down the dimension of T. Any help will be much appreciated. Thank you!
6. ### Write as Sigma...

I'm struggling to put this into Sigma notation... Okay, So this Sigma stuff is challenging to me for some reason... I hope I can figure this out at some point... It really seems to help me when I'm able to see the correct steps and answers, then sort of reverse engineer from the solution...
7. ### Write cot(x) in terms of sin(x)

I had to write cot(t) in terms of sin(t) and it was in the fourth quadrant. I got -square root(1-sin(t)) /sin(t). Do you know why that's wrong and what the correct answer is?
8. ### How to write a spanning set for a polynomial of degree three

How do I get from p to the spanning set? I understand how to get here. p(x) = (x-2)(x-3)(ax+b) How do I get to the spanning set in the image above? I really need to see it step-by-step.
9. ### Is there a way to shorten or write another proof for these problems? :)

Construct a formal proof of validity for each argument. Specifically, I want to find a way to rewrite problems 12-14 :) For the Rules of Inference, I learned so far in the following (bolded parts are conclusion) 1. addition If P, then PvQ 2. simplification If P^Q, then P 3. conjunction P Q...
10. ### Write Distance d

Write the distance d between the point (3,1) and the line y = mx + b in terms of m. When is the distance zero?
11. ### Write A Linear Equation

A real estate office handles an apartment complex with 50 units. When the rent is $580 per month, all 50 units are occupied. However, when the rent is$625, the average number of occupied units drops to 47. Assume that the relationship between the monthly rent p and the demand x is linear. Write...
12. ### Write An Equation

Although I did promise to show my work to posted problems, there's are questions that simply throw me for a loop. Write an equation whose graph has the indicated property. The graph has intercepts at x = -5/2, x = 2 and x = 3/2. The directions go on to say that there may be more than one...
13. ### How to write equation for Parabolas?

y = a(x)^2 What can I do with the Focus to find a? y = a(x)^2 Why is isn't putting 1/8 into 4p giving me a? What is p equals to? a is 2, I'm not sure what the process is.
14. ### Figuring out how to write derivative of a function

The function given is, p(t)=(500)/(1+e^-t) and I solved the derivative as, p'(t)=(500e^-t)/((1+e^-t)^2) but I checked this out in mathway.com and cymath.com and found they have different answers, mathway shows the derivative as 500e^-t(1+e^-t)^-2 and cymath shows it as...
15. ### How to write x in terns of n in this sequence question

The question is attached . I want to know the steps of solving it. Thank you.
16. ### Write trig expression as an algebraic expression containing u and v

I'm stuck on this one: Cos(tan^-1u+tan^-1v) I know you can use cos(a+b)=cosacosb-sinasinb but not sure what to do after.
17. ### Write equation as sum and as product

write 2cos(7t/2)cos(3t/2) as a sum. write cos(75 degrees)+cos(15degrees) as a product, then find the exact value. please explain the answer, thank you!
18. ### How to write a downside arrow over a letter?

Greetings, I would like to put a downside arrow over a letter in LaTeX, how could I do it? I need it for the convective term of the Navier-Stokes equations to mark which velocity the \nabla acts on. Thank you, Zoli
19. ### A strange way to write 0

Let $K \leq 3$ an integer. Prove that $$\underset{i=0}{\overset{K}{\sum}}\frac{\left(-1\right)^{i}}{i!}\frac{\left(K-i-1\right)^{2}}{\left(K-i\right)!}=0.$$
20. ### how to write out an aliasing structure

Hello, I'm having difficulty with this problem started. The question states: Operator collecting data forgot to input the settings for tool angle. Low setting is 15, the high setting is 25. Fill in the settings knowing that the 2^k-1 model was used to collect the data and write out the aliasing...