- #1
beetle2
- 111
- 0
Homework Statement
Let [itex](X,\theta)[/itex] be a metric space. Take [itex] K > 0 [/itex]and define.
[itex]\theta : X \cross X \rightarrow \real_{0}^{+}[/itex], [itex](x,y)\rightarrow \frac{K\phi(x,y)}{1+K\phi(x,y)}[/itex]
Show that [itex](X,\theta)[/itex] is a metric space.
Homework Equations
can someone please check my triangle inequality?
The Attempt at a Solution
[itex]\phi(x,z) \leq \frac{K\phi(x,y)}{1+K\phi(x,y)}[/itex]
[itex]\leq \mid \frac{K\phi(x,y)}{1+K\phi(x,y)}\mid + \mid \frac{K\phi(y,z)}{1+K\phi(y,z)}\mid[/itex]
[itex]= \mid \frac{K\phi(x,y)}{1+K\phi(x,y)} + \frac{K\phi(y,z)}{1+K\phi(y,z)}\mid[/itex]
[itex]=\phi(x,y)+\phi(y,z)[/itex]