Question

Calcula la siguiente suma=
S=1-2+3-4+...+(-1)^kn+1) (n)

Answer 1

Spar = (n/2)(-1)^(n+1) = n/-2

Simpar = (n+1/2)(-1)^(n+1) = (n+1)/2

comprobemos

S(4)=(4/2)(-1)^(4+1)=4/-2
S(4)=(2)(-1)=-2
vemos que -2=-2

S=1-2+3-4=-2

S(3)=(3+1)/2(-1)^(4)=2
S(4)=2(1)=2
2=2

S(3)=1-2+3=2

espero te sirva

saludos Ariel