Răspuns:
1.nu stiu scz
2.a) x/3 * 5/4 = 5x/12
b) 2x/3 * 9/10 = x/3 * 9/5 = x/1 * 3/5 = 3x/5
c) 1si1/3 * x/6 = 4/3 * x/6 = 2/3 * x/3 = 2x/9
d) x/4 * 1/4 = x/16
3.introduci intregii in fractie
1+1/2=3/2
1+1/3=4/3
1+1/4=5/4
..........................
1+1/79=80/79
1+1/80=81/80
Inmultesti termen cu termen
(1+1/2)*(1+1/3)*(1+1/4)*...*(1+1/79)*(1+1/80)=3/2*4/3*5/4*...*81/80 =faci simplificarile=1/2*81=81/2
4.calcul direct
membru drept
(1/k) *(n+k-n)/n(n+k)=(k/k)*(1/n(n+k))=1/n(n+k)
atunci
1/1*3=1/1*(1+2)=(1/2)(1/1-1/3)
1/3*5=1/3*(3+2)=1/2(1/3-1/5)
.................................................
1/89*91=1/89*(89+2) =1/2(1/89-1/91)
si
1/1*3+1/3*5+1/5*7+...+1/89*91=(1/2)*(1/1-1/3+1/3-1/5+...+1/89-1/91)=
(1/2)*(1/1-1/91)=(1/2)*(90/91)=45/91
b) analog
S=(1/4)*(1/1-1/5+1/5-1/9+1/9-1/13+...+1/81-1/85)=
(1/4)*(1/1-1/85)=(1/4)*(1/1-1/85)=(1/4) *(84/85)=21/85
c) analog
S=(1/4) (1/1*2+1/2*3+1/3*4+...+1/35*36) =
(1/4) *(1/1)* (1/1-1/2+1/2-1/3+1/3-1/4+...+1/35-1/36)=
(1/4)*(1-1/36) =(1/4) *(35/36)=35/144
d) analog
S= (1/3) (1/1-1/4+1/4-1/7+1/7-1/10+...+1/88-1/91)=
(1/3) (1/1-1/91)=(1/3) *(90/91)=30/91
Explicație pas cu pas:
sper ca te-am ajutat si sper sa imi dai coroana
