а) 48, 12,...
b1 = 48, q = 1/4
b6 = b1*q^5 = 48/4^5 = 3/64
bn = b1*q^(n-1) = 48/4^(n-1) = 3*(4^(3-n))
б) 64/9, -32/3...
b1 = 64/9, q = - 3/2
b6 = b1*q^5 = - 64*243/(9*32) = -54
bn = b1*q^(n-1) = (64/9)*(-3/2)^(n-1)
в) -0,001; -0,01...
b1 = -0,001; q = 10
b6 = b1*q^5 = -0,001*10^5 = -100
bn = b1*q^(n-1)= -0,001* 10^(n-1) = -10^(n-4)
г) -100, 10....
b1= -100; q = -0,1
b6 = b1*q^5 = 100 *(-10)^(-5) = -0,001
bn = b1*q^(n-1) = 100*(-0,1)^(n-1)
5х-1,2 = -7,4-1,9х
5х+1,9х = -7,4+1,2
6,9х = -6,2
х = -6,2 : 6,9
х = -62/69
Ответ в приложении ХХХХХХХХХХХХХ
(cos(y+x)-cos(y-x))/2=(-sinx)*siny
4x2•y3/y•12x3=y3/3x
/-деление(дробь)