In the drawing, four main structures of the series.
Choose the algebraic expression corresponding to the number of points in place of
We have hundreds of course questions with personalized recommendations + Account 100% premium
In the drawing, four main structures of the series.
Choose the algebraic expression corresponding to the number of points in place of
The aim is to find a formula for the number of points (or dots) in structure based on the input . Let's consider the visible pattern in the structures:
By considering four instances, we deduce:
Observing closely, each subsequent structure increases by 2 points consistently.
Now, we try to formulate this pattern algebraically:
The number of points seems directly proportional to , leading to the formula , where each increase in results in 2 additional points.
Verify:
The pattern and derived expression consistently apply.
Thus, the answer is .
From the choices provided, the correct algebraic expression for the number of points in place of corresponds directly to choice 2: .
Is there a term-to-term rule for the sequence below?
18 , 22 , 26 , 30
Look at the simplest structure first. The leftmost structure with 2 points represents n=0, then count sequentially: n=1 has 4 points, n=2 has 6 points, and so on.
Multiple formulas can describe the same pattern! For example, equals . Always expand and simplify to check if your answer matches the given choices.
Focus on counting total points in each structure, not their arrangement. Write down the sequence: 2, 4, 6, 8... then look for the common difference between consecutive terms.
Yes! Test each formula with the given structures. For n=0, n=1, n=2, n=3, check which formula gives 2, 4, 6, 8 points respectively. This is a great way to verify your pattern.
The '+1' accounts for the fact that we start counting at n=0 but still need 2 points minimum. It shifts the pattern so that when n=0, we get 2(0+1) = 2 points, not 0 points.
Get unlimited access to all 18 Series questions, detailed video solutions, and personalized progress tracking.
Unlimited Video Solutions
Step-by-step explanations for every problem
Progress Analytics
Track your mastery across all topics
Ad-Free Learning
Focus on math without distractions
No credit card required • Cancel anytime