frac{sum_t=1^nfrac{I_{t}+M_{t}+F_{t}}{(1+r)^t}}{sum_t=1^nfrac{E_{t}}{(1+r)^t}} lösen

$$\frac { \sum _ { t = 1 } ^ { n } \frac { I _ { t } + M _ { t } + F _ { t } } { ( 1 + r ) ^ { t } } } { \sum _ { t = 1 } ^ { n } \frac { E _ { t } } { ( 1 + r ) ^ { t } } }$$

Auswerten

$$\frac{F_{t}+I_{t}+M_{t}}{E_{t}}$$

W.r.t. I_t differenzieren

$$\frac{1}{E_{t}}$$