What is the Variance of Brownian motion

265 Views Asked by At

Consider two instances of Brownian motion, B1 and B2. What would the variance of B1 and B2 be? So var(B1+B2)? I know B1 and B2 are not independent but B2-B1 and B1 are.

1

There are 1 best solutions below

0
On

hint

The variance of $B_1$ and $B_2$ (or more importantly the variance of $B_1$ and $B_2-B_1$) can be read off from the definition of Brownian motion. You are right about which things are independent and which aren't. Observe that $B_1+B_2 = (B_2-B_1) + 2B_1.$