Friedmann equations questions

(a) If we live in a matter-dominated (dust) Friedmann Universe with M (t0) = 1.1 today, show that the scale factor a will increase to a maximum value, amax = 11 a0.

(b) Using the Friedmann equation, show that, if M (z = 0) = 0.27 today, M (a) at z = 1100 (the surface of last scattering for CMB photons) was equal to 0.99755 (assume = rad = 0).

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