Question

Q=-2 bn=-4 Sn=-63\24 найдите b1 и n ?

Answer 1

Ответ:

b₁=0,125; n=6

Объяснение:

Sₙ=(b₁-bₙ·q)/(1-q)

-63/24=(b₁-(-4)·(-2))/(1-(-2))

-63/24=(b₁-8)/3

-63=8·(b₁-8)

-63=8b₁-64

8b₁=64-63

b₁=1/8=0,125

bₙ=b₁·qⁿ⁻¹

bₙ=b₁·qⁿ⁻¹

-4=1/8 ·(-2)ⁿ⁻¹

(-2)ⁿ⁻¹=-4/(1/8)

(-2)ⁿ⁻¹=-4·8

(-2)ⁿ⁻¹=-32

(-2)ⁿ⁻¹=(-2)⁵

n-1=5

n=5+1=6

Answer 2

To find the values of b1 and n in the given equation Q = -2bn = -4Sn = -63/24, we need to isolate each variable and solve for them individually.

Let's start with the equation Q = -2bn:

Q = -2bn -2bn = Q Divide both sides by -2: bn = Q/(-2) bn = Q/-2

Next, let's consider the equation -2bn = -4Sn:

-2bn = -4Sn Divide both sides by -2: bn = 2Sn

Now we have two expressions for bn, so we can equate them:

Q/-2 = 2Sn Q = -4Sn

Since Q is equal to -63/24, we can substitute it in:

-63/24 = -4Sn

To solve for Sn, we divide both sides by -4:

Sn = (-63/24) / -4 Sn = (63/24) / 4 Sn = 63/96 Sn = 21/32

Now, we substitute Sn back into the equation bn = 2Sn:

bn = 2(21/32) bn = 42/32 bn = 21/16

Therefore, the values of b1 and n are b1 = 21/16 and n = 21/32, respectively.