A positive 3430. because two negatives that are being multiplied by eachother are automatically positive.
Okay first I think you might’ve highlighted incorrectly. You want to make sure the angles match with each other. Next you set up a proportion and solve. I’ll draw this all out for you. I hope this helps! :))
Answer:
![W=\{\left[\begin{array}{ccc}a+2b\\b\\-3a\end{array}\right]: a,b\in\mathbb{R} \}](https://tex.z-dn.net/?f=W%3D%5C%7B%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Da%2B2b%5C%5Cb%5C%5C-3a%5Cend%7Barray%7D%5Cright%5D%3A%20a%2Cb%5Cin%5Cmathbb%7BR%7D%20%5C%7D)
Observe that if the vector
is in W then it satisfies:
![\left[\begin{array}{ccc}x\\y\\z\end{array}\right]=\left[\begin{array}{c}a+2b\\b\\-3a\end{array}\right]=a\left[\begin{array}{c}1\\0\\-3\end{array}\right]+b\left[\begin{array}{c}2\\1\\0\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Dx%5C%5Cy%5C%5Cz%5Cend%7Barray%7D%5Cright%5D%3D%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7Da%2B2b%5C%5Cb%5C%5C-3a%5Cend%7Barray%7D%5Cright%5D%3Da%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7D1%5C%5C0%5C%5C-3%5Cend%7Barray%7D%5Cright%5D%2Bb%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7D2%5C%5C1%5C%5C0%5Cend%7Barray%7D%5Cright%5D)
This means that each vector in W can be expressed as a linear combination of the vectors ![\left[\begin{array}{c}1\\0\\-3\end{array}\right], \left[\begin{array}{c}2\\1\\0\end{array}\right]](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7D1%5C%5C0%5C%5C-3%5Cend%7Barray%7D%5Cright%5D%2C%20%5Cleft%5B%5Cbegin%7Barray%7D%7Bc%7D2%5C%5C1%5C%5C0%5Cend%7Barray%7D%5Cright%5D)
Also we can see that those vectors are linear independent. Then the set
is a basis for W and the dimension of W is 2.
Well x is an obtuse angle
but the angle e,f,g is an acute angle
#1) A
#2) E
#3) C
#4) 0.5840
#5) 0.6945
#6) 0.4911
#7) D
#8) G
#9) 0.4375
#10) 0.5203
The formula we use for this is

,
where

is the speed of sound, f is the frequency (or pitch) of the note, and λ is the wavelength.
#1) 0.77955f = 343
Divide both sides by 0.77955:
0.77955f/0.77955 = 343/0.77955
f = 439.997 ≈ 440. This is the pitch for A.
#2) 0.52028f = 343
Divide both sides by 0.52028, and we get f = 659.260. This is the pitch for E.
#3) 0.65552f = 343
Divide both sides by 0.65552, and we get f = 523.25. This is the pitch for C.
#4) 587.33λ = 343
Divide both sides by 587.33 and we get λ = 0.583999 ≈ 0.5840.
#5) 493.88λ = 343
Divide both sides by 493.88, and we get λ = 0.6945.
#6) 698.46λ = 343
Divide both sides by 698.46 and we get λ = 0.49108 ≈ 0.4911.
#7) 0.5840f = 343
Divide both sides by 0.5840 and we get f = 587.3288 ≈ 587.33. This is the pitch for D.
#8) 0.4375f = 343
Divide both sides by 0.4375 and we get f = 784. This is the pitch for G.
#9) 783.99λ = 343
Divide both sides by 783.99 and we get λ = 0.4375.
#10) 659.26λ = 343
Divide both sides by 659.26 and we get λ = 0.52028 ≈ 0.5203.