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  • In an Amino Acid, does the R group differentiates the amino acid so its a completely different molecule?

    1. I mean, is it only the R group in the amino acid which differentiates it into a different type of amino acid?
      I heard there are about 20 different types of amino acids in animals is the R group responsible for it?

      Answer by Oaktree
      Yes, the R group distinguishes one amino acid from another, at least in the standard amino acids.

    2. 500 Heads after flipping a fair coin 1000 time.

      R programming is kinda like MATLAB, so if you only know how to do it in matlab can you still give me that code because they’re basically the same.

      Answer by ℛєȶгѳჵɑɱεг ≡ ᏳᎢ4▐▐ Ꭺᴜτø Ꮪᴘᴇჺɪᴀʟɪτᴀ
      Use the information shown here to help you: http://cran.r-project.org/web/packages/IPSUR/vignettes/IPSUR.pdf

    3. I have this Math problem in which requires me to find the possible values for r:

      The volume of a torus is give by the formula V=2 * π^2 * r^2 * R where r and R are the radii shown and r is equal or less than R.
      A metal ring in the shape of a torus has a volume of 100 cubic centimeters. Choose three possible values of r, and find the corresponding values of R.

      I don’t know how to find the possible values of r. Many of the numbers I have randomly tried give the result that r is greater than R, which is incorrect. Could you please make it clear for me in this problem?

      Thank you very much!

      Answer by Scarlet Manuka
      Like most problems, it helps if you think about things a little bit before rushing in.

      π² is roughly 10, so if we want V = 100 = 2π² r² R, we’re going to need r² R to be around 5 or so. So you can’t choose e.g. r = 2 cm, since then you’d be looking at R around 1.25; you need smaller values of r.

      Now, to actually finding R: we already said 100 = 2π² r² R, and it’s pretty easy see that we can rearrange that to give R = 100 / (2π² r²) = 50 / (π² r²).

      So choose some values of r:
      r = 1 cm => R = 50 / π² = 5.07 cm (3sf)
      r = 0.5 cm => R = 50 / (π² (0.5)²) = 20.3 cm (3sf)
      r = 1.5 cm => R = 50 / (π² (1.5)²) = 2.25 cm (3sf)

      With a little thought you should be able to see that the value you choose for r must be less than the cube root of 50 / π², i.e. 1.717 cm (4sf), in order to have R > r. Any positive number less than this will be fine.