Welcome to understanding nth terms in sequences!An nth term is a special formula that helps us find any number in a sequence.Let's look at a simple sequence: two, four, six, eight.Each number in the sequence has a position. The first number is at position one, the second at position two, and so on.This sequence continues following the same pattern. Each term's position helps us understand how to find any number in the sequence.Let's look at some examples of how position numbers help us find terms in the sequence.Now that we understand what an nth term is, we can learn how to find the pattern in sequences.To identify the pattern in a sequence, we look at the difference between consecutive terms.Let's add arrows to show how we move from one term to the next.Notice that each time we move to the next number, we add three.This constant difference of plus three is what makes this an arithmetic sequence.Let's look at another sequence with a different pattern.Again, we'll mark the differences between consecutive terms.This time, we're adding five each time. This is our new common difference.Now let's examine a sequence that decreases instead of increases.Watch how the difference is now negative as we move from term to term.The common difference is negative three, showing that arithmetic sequences can also decrease.Let's summarize what we've learned about identifying patterns in arithmetic sequences.First, we find the differences between consecutive terms.Then, we verify that this difference stays constant throughout the sequence.Finally, remember that the common difference can be either positive or negative.To build our formula, we start with our sequence: two, five, eight, eleven, fourteen.We identified that the common difference between terms is plus three.This common difference of three becomes the coefficient of n in our formula.When we multiply n by three, this creates the pattern of increasing by three each time.Now let's build our formula step by step. We start with three n, and we'll need to add or subtract something to get the correct terms.Let's use the first term to find what we need to add. When n equals one, we want the term to be two.Simplifying the right side: three plus k should equal two.Therefore, k must equal negative one.So our complete formula is three n minus one.Let's verify this works for each position in our sequence.Now that we have our sequence and know the pattern, let's find the starting number.We start with our basic formula using just the pattern we found: three n.To find the starting number, we substitute n equals one into our formula.This gives us three.However, looking at our sequence, we can see the first term is actually five.The difference between what we got and what we need is two.Therefore, we need to add two to our formula to make it work for all terms.Let's verify this works by creating a table to check each term.Remember these key points when finding the starting number: Compare the formula's output with the actual first term, find the difference needed, and add or subtract that difference in your formula.Now that we have our complete formula, we can move on to testing it with different values.To verify our formula T_n equals 3n plus 2, let's test it with different values of n.We'll create a table to organize our calculations.Let's start by testing the first few terms of our sequence.Now, let's try a more distant term. When n equals 10...And for a really far term, let's try n equals 100...Notice how each result follows our sequence pattern, increasing by 3 each time.Since our formula generates the correct terms for both nearby and distant positions, we can verify it works for any value of n.Let's review what we've learned about verifying nth term formulas.Thanks for learning about nth terms with Spark.E!
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