`B=(\sqrtb/(a-\sqrt{ab})-\sqrta/(\sqrt{ab}-b)).(a\sqrtb-b\sqrta)`
`(a>0,b>0,a\neb)`
`B=(\sqrtb/(\sqrta(\sqrta-\sqrtb))-\sqrta/(\sqrtb(\sqrta-\sqrtb))).(a\sqrtb-b\sqrta)`
`B=((\sqrtb)^2/(\sqrt{ab}(\sqrta-\sqrtb))-(\sqrta)^2/(\sqrt{ab}(\sqrta-\sqrtb))).(a\sqrtb-b\sqrta)`
`B=(b/(\sqrt{ab}(\sqrta-\sqrtb))-a/(\sqrt{ab}(\sqrta-\sqrtb))).(a\sqrtb-b\sqrta)`
`B=(b-a)/(\sqrt{ab}(\sqrta-\sqrtb)).sqrt{ab}(\sqrta-\sqrtb)`
`B=((b-a)sqrt{ab}(\sqrta-\sqrtb))/(\sqrt{ab}(\sqrta-\sqrtb)`
`B=b-a`