If the 4th and 7th terms of a G. P are −1/2 and
− 4, respectively, then find G5 and S6 .

G5 = -1

S6 = -63/16

Step-by-step explanation:

The formula for finding the nth term of a GP is Tn = ar^n-1

a is the first term

r is the common ratio

n is the number of terms

If the 4th term is -1/2

T4 = ar^4-1

T4 = ar³ = -1/2 1

If the 7th term is -4

T7 = ar^7-1

T7 = ar^6 = -4 2

Divide both equation

ar^6/ar³ = -4/(-1/2)

r³ = -4×-2

r³ = 8

r = 2

Common ratio is 2

Since ar³ = -1/2

a(2)³ = -1/2

8a = -1/2

a = -1/16

The first term is -1/16

Get the fifth term G5

G5 = ar⁴

G5 = (-1/16)(2)⁴

G5 = (-1/16)(16)

G5 = -1

Get the sum of the first six terms S6

S6 = a(r^n-1)/r-1

S6 = -1/16(2^6-1)/2-1

S6 = -1/16(64-1)

S6 = -63/16

Hence the sum of the first six terms is -63/16

this story was prepared by jim

mccullaugh in los angeles and

al stewart in new york.

new york the colossal success of "top gun" appears to have dramatically altered madison avenue's

perception of corporate sponsorship

of home video projects.

the paramount home video re- lease, featuring a 60- second diet

pepsi spot, was by no means the

first prerecorded video to carry an advertiser's plug, but it was the

first major theatrical release to do so. in the aftermath of the title's

success, paramount is widely ex- pected to ink a similar deal for

"crocodile dundee" or "star trek

iv" or both.

corporate america's new attraccds push british

recording sales

to 19% gain

london fueled by the compact

disk boom, the value of u.k. manu- facturer shipments of recordings

rose 19% in the 12 -month period ended march 1987, according to the

british phonographic industry.

total value of u.k. shipments for

the period was $755 million for all

configurations. (all value figures

are based on an exchange rate of

$1.68 to the pound sterling.)

cd sales totaled 10.7 million units

worth $121.3 million- compared

with 3.7 million units worth $39.5

million in the prior 12 months -and

accounted for two -thirds of the

overall gain in trade value. at present growth rates, says the bpi, cd

sales for calendar 1987 will reach 20

(continued on page 79)

step-by-step explanation:

the answer is c.

step-by-step explanation: