1)х-число членов,тогда сумма равна 17х
17х-х=112
16х=112
х=112Ж16=7
2)a9=a1q^8=64*1/126=1/4
S13=a1*(1-q^13)/(1-q)=64*(1-1/8192):1/2=64*8191/8192*2=8191/64=127 63/64
Решение
1) 1 (3/4) * (√2 / √9) = 7/4 * √(2/98) = 7/4 * √1/49 = 7/4 * 1/7 = 1/4
2) (2x + 3) / [4(x - 1) + 3] = 1/4
4*(2x + 3) = 4(x - 1) + 3
8x + 12 = 4x - 4 + 3
8x - 4x = - 1 - 12
4x = - 13
x = - 13/4
x = - 3,25
<span>arccos (sin(-п/4))=arccos(-√2/2)=pi-arccos(√2/2)=pi-pi/4=3pi/4</span>
F(x) = -4x + 4x = -1
f(x) = 10x = -1
f(x) = -0,1