(20 points) (a) (5 points) Write down the Kolmogorov forward differential equation for p in the joint life model illustrated in the fitgure below. (b) (15 points) Using (a), or otherwise, prove that 1- Ary xy = 8 ,01 Hx+r:y+! Husband Alive Wife Alive 0 Husband Alive Wife Dead 1 ,02 ,13 Hx+r:+1 ,23 Myti Husband Dead Wife Alive 2 Husband Dead Wife Dead 3 (20 points) (a) (5 points) Write down the Kolmogorov forward differential equation for p in the joint life model illustrated in the fitgure below. (b) (15 points) Using (a), or otherwise, prove that 1- Ary xy = 8 ,01 Hx+r:y+! Husband Alive Wife Alive 0 Husband Alive Wife Dead 1 ,02 ,13 Hx+r:+1 ,23 Myti Husband Dead Wife Alive 2 Husband Dead Wife Dead 3