  Combining galaxy cluster data from the ROSAT All-Sky Survey and the Chandra
X-ray Observatory, cosmic microwave background data from the Wilkinson
Microwave Anisotropy Probe, and galaxy clustering data from the WiggleZ Dark
Energy Survey, the 6-degree Field Galaxy Survey and the Sloan Digital Sky
Survey III, we test for consistency the cosmic growth of structure predicted by
General Relativity (GR) and the cosmic expansion history predicted by the
cosmological constant plus cold dark matter paradigm (LCDM). The combination of
these three independent, well studied measurements of the evolution of the mean
energy density and its fluctuations is able to break strong degeneracies
between model parameters. We model the key properties of cosmic growth with the
normalization of the matter power spectrum, sigma_8, and the cosmic growth
index, gamma, and those of cosmic expansion with the mean matter density,
Omega_m, the Hubble constant, H_0, and a kinematical parameter equivalent to
that for the dark energy equation of state, w. For a spatially flat geometry,
w=-1, and allowing for systematic uncertainties, we obtain sigma_8=0.785+-0.019
and gamma=0.570+0.064-0.063 (at the 68.3 per cent confidence level). Allowing
both w and gamma to vary we find w=-0.950+0.069-0.070 and gamma=0.533+-0.080.
To further tighten the constraints on the expansion parameters, we also include
supernova, Cepheid variable and baryon acoustic oscillation data. For w=-1, we
have gamma=0.616+-0.061. For our most general model with a free w, we measure
Omega_m=0.278+0.012-0.011, H_0=70.0+-1.3 km s^-1 Mpc^-1 and
w=-0.987+0.054-0.053 for the expansion parameters, and sigma_8=0.789+-0.019 and
gamma=0.604+-0.078 for the growth parameters. These results are in excellent
agreement with GR+LCDM (gamma~0.55; w=-1) and represent the tightest and most
robust simultaneous constraint on cosmic growth and expansion to date.
