Mohon bantuannya hitung jumlah 7 suku pertama -2+1-1/2+1/4-.....

Merupakan barisan geometri
a = -2
r = 1 : -2 = -½

U1 = -2
U2 = 1
U3 = -½
U4 = ¼
U5 = -⅛
U6 = 1/16
U7 = -1/32

-2+1+(-½)+(¼)+(-⅛)+(1/16)+(-1/32)
= -1-(½)+(¼)-(⅛)+(1/16)-(1/32)
= -3/2+(¼)-(⅛)+(1/16)-(1/32)
= -5/4-(⅛)+(1/16)-(1/32)
= -11/8+(1/16)-(1/32)
= -21/16-(1/32)
= (-43/32)

Maaf kalo salah