x > 7 x < 10
7 o---------------------o 10
This is not an empty set. x contains all of the values between 7 and 10.
Answer:
the common ratio is either 2 or -2.
the sum of the first 7 terms is then either 765 or 255
Step-by-step explanation:
a geometric sequence or series of progression (these are the most common names for the same thing) means that every new term of the sequence is created by multiplying the previous term by a constant factor which is called the common ratio.
so,
a1
a2 = a1×f
a3 = a2×f = a1×f²
a4 = a3×f = a1×f³
the problem description here tells us
a3 = 4×a1
and from above we know a3 = a1×f².
so, f² = 4
and therefore the common ratio = f = 2 or -2 (we need to keep that in mind).
again, the problem description tells us
a2 + a4 = 30
a1×f + a1×f³ = 30
for f = 2
a1×2 + a1×2³ = 30
2a1 + 8a1 = 30
10a1 = 30
a1 = 3
for f = -2
a1×-2 + a1×(-2)³ = 30
-10a1 = 30
a1 = -3
the sum of the first n terms of a geometric sequence is
sn = a1×(1 - f^(n+1))/(1-f) for f <>1
so, for f = 2
s7 = 3×(1 - 2⁸)/(1-2) = 3×-255/-1 = 3×255 = 765
for f = -2
s7 = -3×(1 - (-2)⁸)/(1 - -2) = -3×(1-256)/3 = -3×-255/3 =
= -1×-255 = 255
X= -10
You may review the image Ive attached to see how I got this answer.
The value of x in the secants intersection is 1 units
The value of NM in the tangent and secant intersection is 51 units
<h3>How to find length when secant and tangent intersect?</h3>
The first question, two secant intersect outside the circle.
Therefore,
(6x + 8x)8x = (9 + 7)7
14x(8x) = 16(7)
112x² = 112
x² = 112 / 112
x = √1
x = 1
The second question, tangent and secant intersect,
Therefore,
(x + 3)² = (x - 3)(16 + x - 3)
(x + 3)² = (x - 3)(x + 13)
(x + 3)(x + 3) = (x - 3)(x + 13)
x² + 3x + 3x + 9 = x² + 13x - 3x - 39
x² + 9x + 9 = x² + 10x - 39
x² - x² + 9x - 10x = -39 - 9
-x = - 48
x = 48
NM = 48 + 3 = 51 units
learn more on secant and tangent here: brainly.com/question/12477905
#SPJ1
Answer:
{13.7, 13,7/100 –13,17/100 –13.2}
Step-by-step explanation:
