How to divide a vector by a constant?

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Lance Shallenberger 2021-9-16

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https://ww2.mathworks.cn/matlabcentral/answers/1454859-how-to-divide-a-vector-by-a-constant

评论： Lance Shallenberger 2021-9-16

c=3*10^8
c = 300000000
speeds=(.1*c:.9*c/8:.9*c)
speeds = 1×8
    30000000    63750000    97500000   131250000   165000000   198750000   232500000   266250000
y=1/sqrt(1-(speeds.^2./c^2))
Error using /
Matrix dimensions must agree.

What is my error?

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Answer 1

Image Analyst 2021-9-16

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The denominator with sqrt() is a vector so you need a dot before the slash

y = 1 ./ sqrt(1 - (speeds .^ 2 ./ c ^ 2))

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Lance Shallenberger 2021-9-16

thanks!

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Answer 2

Cris LaPierre 2021-9-16

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You need to use elementwise division everywhere in your equation for y

c=3*10^8;
speeds=(.1*c:.9*c/8:.9*c);
%  v
y=1./sqrt(1-(speeds.^2./c^2))
y = 1×8
    1.0050    1.0234    1.0574    1.1121    1.1974    1.3350    1.5824    2.1701