The first term is 1 in the geometric sequence 1,-3,9,-27,...what is the seventh term of the geometric sequence?
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Answer:
The slope of NP is ⇒ B
Step-by-step explanation:
- In any square, every two opposite sides are parallel and every two consecutive sides are perpendicular
- Parallel lines have the same slope
- The product of the slopes of the perpendicular lines is -1, which means if the slope of one m, then the slope of the other is
(reciprocal m and change its sign)
- The rule of the slope of the line which passes through the points (x1, y1) and (x2, y2) is m =
In square MNPR
∵ MN and NP are adjacent sides
∴ MN ⊥ NP
∵ M = (3, 8) and N = (-2, 1)
∴ x1 = 3 and y1 = 8
∴ x2 = -2 and y2 = 1
→ Use the rule of the slope above to find the slope of MN
∴ m(MN) =
∴ m(MN) =
∴ m(MN) =
∵ MN ⊥ NP
∴ The product of their slopes = -1
→ Reciprocal the slope of MN and change its sign
∴ m(NP) =
∴ The slope of NP is
The value of d is -2
Step-by-step explanation:
The nth term of the arithmetic sequence is , where
is the first term
- d is the common difference between each 2 consecutive terms
The nth term of the geometric sequence is , where
- r is the common ratio between each two consecutive terms
∵ of an arithmetic sequence is 1
∵ The common difference is d, where d ≠ 0
∵ ,
,
are the first 3 terms of a geometric sequence
∵ = 1 + (2 - 1)d
∴ = 1 + d
∵ = 1 + (3 - 1)d
∴ = 1 + 2d
∵ = 1 + (6 - 1)d
∴ = 1 + 5d
∴ The first 3 terms of the geometric sequence are (1 + d) , (1 + 2d) ,
(1 + 5d)
∵ The common ratio in the geometric sequence is
∴
- Use cross multiplication with the equal fractions
∵
∴ (1 + 2d)(1 + 2d) = (1 + d)(1 + 5d)
∴ 1 + 2d + 2d + 4d² = 1 + 5d + d + 5d²
- Add like terms in each side
∴ 1 + 4d + 4d² = 1 + 6d + 5d²
- Subtract 1 from both sides
∴ 4d + 4d² = 6d + 5d²
- Subtract 4d from both sides
∴ 4d² = 2d + 5d²
- Subtract 4d² from each side
∴ 0 = 2d + d²
- Take d as a common factor
∴ 0 = d(2 + d)
- Equate each factor by 0
∴ d = 0 but we will reject it because d ≠ 0
∴ 2 + d = 0
- Subtract 2 from both sides
∴ d = -2
The value of d is -2
Learn more:
You can learn more about the sequence in brainly.com/question/1522572
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