the sum of the first six terms of a G. P is 9 times the sum of the first three terms . what is the first term ?

Without any more information, the first term can be any number.

Let a be the first term in the geometric progression, and let r be the common ratio between consecutive terms. Then

a + ar + ar ² + ar ³ + ar ⁴ + ar ⁵ = 9 (a + ar + ar ²)

ar ³ + ar ⁴ + ar ⁵ = 8 (a + ar + ar ²)

r ³ + r ⁴ + r ⁵ = 8 (1 + r + r ²)

r ³ (1 + r + r ²) = 8 (1 + r + r ²)

r ³ = 8

r = 2

Now with this ratio, the sum of the first six terms is

a (1 + r + r ² + r ³ + r ⁴ + r ⁵) = a (1 - r ⁶)/(1 - r) = 63a

while the sum of the first three terms is

a (1 + r + r ²) = a (1 - r ³)/(1 - r) = 7a

and of course 63a = 9 • 7a, and this is true for any a.

the answer is b.

step-by-step explanation:

by the trigonometric ratio tangent, tangent equals opposite divided by adjacent.

therefore, tan(50) equals ac/3

multiply each side by 3 to get: ac=3tan(50)

the answer is b.