A numerical approximation - GRE Mathematics Subject Test

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  • Опубліковано 8 січ 2025

КОМЕНТАРІ •

  • @RajSandhu-gm8iz
    @RajSandhu-gm8iz 29 днів тому

    Quite a neat quick answer you did . I wrote √1.5 as √3/√2 .
    I then wrote 266 in prime factors 266=(2 x 7 x19), then distributed the exponential 3/2 to each term and then split each term, for instance 2^3/2 becomes 2 x 2^½.
    Did the same with the other terms. Multiplied all the integer terms to get 266, put all √terms together to get √401
    End up with ≈ 266 x 20, hence 5320 and E. Yours was quicker.

  • @anandkulkarni2111
    @anandkulkarni2111 28 днів тому +1

    My line of thought with out anything [ pen/paper/writing ].
    Step 1. (266) ^ 3/2 = (sqrt(266))^3 ~= (16.2)^3 ~= 256*16.2 ~= 4000+ (definitely). Call this result p.
    Step 2. p * sqrt(1.5) ~= 1.35ish * p ~= 1.35 * (>4000) ~= 5.2 or 5.3K.
    Answer is 5300.

  • @amritlohia8240
    @amritlohia8240 7 днів тому +1

    4096*1.2 is in fact 4915.2, so your approach doesn't quite work at the end, but it's still clearly more than 4100, so that's good enough given the multiple-choice answers.

    • @mathoutloud
      @mathoutloud  7 днів тому +1

      Sometimes good enough is good enough haha!

  • @mscha
    @mscha 29 днів тому

    My strategy: square everything. Calculate 1.5 × 266³ and figure out which answer squared is closest. (I got answer A because I completely messed up my calculations. ;-) )

  • @dan-florinchereches4892
    @dan-florinchereches4892 29 днів тому +2

    1.5^0.5*(266)^(3/2)=266*(1.5*266)^.5=266*(3*133)^.5=266*(399)^0.5

    • @mathoutloud
      @mathoutloud  29 днів тому

      That happens to me far too often in my videos, no shame in making mistakes if you use them as motivation to keep sharper.

  • @pietergeerkens6324
    @pietergeerkens6324 29 днів тому +2

    Simplifies to 266 * sqrt(1.5 * 266), which is 266 * sqrt(399) giving about 266 * 20; so (E).