Calcular : 11 + 21 + 31 + 41 + ?
Calcular : 11 + 21 + 31 + 41 + . …. + 151.
Calcular : 11 + 21 + 31 + 41 + . …. + 151.
En resumen
Calcular : 11 + 21 + 31 + 41 + . …. + 151hallamos la razonr = 21 - 11r = 10hallamos el numero de terminosn = <img src="https://tex.z-dn.net/?f=%5Cfrac%7Btn%20-%20t1%7D%7Br%20%7D" /> + 1n = <img src="https://tex.z-dn.net/?
Calcular : 11 + 21 + 31 + 41 + .
…. + 151hallamos la razonr = 21 - 11r = 10hallamos el numero de terminosn = <img src="https://tex.z-dn.net/?f=%5Cfrac%7Btn%20-%20t1%7D%7Br%20%7D" /> + 1n = <img src="https://tex.z-dn.net/?f=%5Cfrac%7B151%20-%2011%7D%7B10%7D" /> + 1n = <img src="https://tex.z-dn.net/?f=%5Cfrac%7B140%7D%7B10%7D" /> + 1n = 14 + 1n = 15ahora hallamos la sumaS = 11 + 21 + 31 + 41 + .
…. + 151S = (<img src="https://tex.z-dn.net/?f=%5Cfrac%7Bt1%20%2B%20tn%7D%7B2%7D" /> )nS = (<img src="https://tex.z-dn.net/?f=%5Cfrac%7B11%20%2B%20151%7D%7B2%7D" /> )10S = (<img src="https://tex.z-dn.net/?f=%5Cfrac%7B162%7D%7B2%7D" /> )10S = (81)10S = 810.