convert real numbers to img form

hi.i have real number which i want to convert t img form. how can i do this?

e.g: 8 to 8i

tnx

Answer 1

[Chunru]

a = 8

a = 8

b = a*1i                % method 1

b = 0.0000 + 8.0000i

c = complex(0, a)       % method 2

c = 0.0000 + 8.0000i

[John D'Errico]

+1 of course, as this seems to cover the bases completely.

I would only add that MATLAB does not have a purely imaginary form, only a complex form. Since the OP seems to be hoping to see a number of the form 8i, they may become confused when seeing a zero real part displayed. If the real part is zero, then the result is purely imaginary.