Whats the answer to 10/y = 2/9
2 answers:
You might be interested in
Morse code is essentially the same as binary. That is, there are two "digits", a dot or a dash.
There are 26 letters in the English alphabet. Clearly, we can't just use one dot or dash, since that could only encode 2 letters at the most. We can't use two symbols because that could only encode 4 letters at the most. Similarly, 3 symbols means
letters at most.
We have to select the smallest power of 2 that exceeds or is equal to 26. In this case,
, so we would have to use up to 5 symbols to encode each letter in the alphabet.
There are 26 letters in the English alphabet. Clearly, we can't just use one dot or dash, since that could only encode 2 letters at the most. We can't use two symbols because that could only encode 4 letters at the most. Similarly, 3 symbols means
We have to select the smallest power of 2 that exceeds or is equal to 26. In this case,
Assuming the area below the line y=0 (i.e. x>1) does NOT count, the area to be rotated is shown in the graph attached.
A. Again, using Pappus's theorem,
Area, A = (2/3)*1*(1-(-1))=4/3 (2/3 of the enclosing rectangle, or you can integrate)
Distance of centroid from axis of rotation, R = (2-0) = 2
Volume = 2 π RA = 2 π 2 * 4/3 = 16 π / 3 (approximately = 16.76 units)
B. By integration, using the washer method
Volume =
![=2\pi[x^4/4-2x^3/3-x^2/2+2x]_{-1}^{1}](https://tex.z-dn.net/?f=%3D2%5Cpi%5Bx%5E4%2F4-2x%5E3%2F3-x%5E2%2F2%2B2x%5D_%7B-1%7D%5E%7B1%7D)
![=2\pi([1/4-2/3-1/2+2]-[1/4+2/3-1/2-2])](https://tex.z-dn.net/?f=%3D2%5Cpi%28%5B1%2F4-2%2F3-1%2F2%2B2%5D-%5B1%2F4%2B2%2F3-1%2F2-2%5D%29)
= 16 π /3 as before
A. Again, using Pappus's theorem,
Area, A = (2/3)*1*(1-(-1))=4/3 (2/3 of the enclosing rectangle, or you can integrate)
Distance of centroid from axis of rotation, R = (2-0) = 2
Volume = 2 π RA = 2 π 2 * 4/3 = 16 π / 3 (approximately = 16.76 units)
B. By integration, using the washer method
Volume =
= 16 π /3 as before