<t>Eqn 3 defines the distribution of dW_q(t) but under the p probability measure.I.e, under p, dW_q(t) ~ N((mu-r)/sigma dt, dt) (ps - I think you made a small error when you wrote your question , the distribuition of the increments for dW_p(t) are normal(0, dt) and not N(0,1) )The next step in the m...