[R] Normal distribution with R

[guox at ucalgary.ca]

If we knew two pth quantiles for a normal distribution,
is it possible that we can find mean and sigma for the normal distribution
using R?

Let x ~ norm(mean, sigma).
Suppose that qnorm(0.9,mean,sigma) and qnorm(0.1,mean,sigma) are known.
Can we find mean and sigma using R?

Thanks,

-james