Chapter 13: Q. 10 (page 870)

.What is the 33rd term in the sequence $- 3, 1, 5, 9, . . . . . . . . . .$ ? What is the sum of the first 20 terms?

Short Answer

Expert verified

The 33rd term of the given sequence is 125.
The sum of first 20 terms of the sequence is 700.

Step by step solution

Step 1. Given information

Sequence is: $- 3, 1, 5, 9, . . . .$

Step 2. To find 33rd term of the sequence.

Since in the given sequence the difference between consecutive terms is constant.

Hence, The sequence is an arithmetic sequence.

First term of the sequence : $a = - 3$

Common difference is : $d = 1 - (- 3) = 1 + 3 = 4$

For 33rd term : $n = 33$

So, 33rd term is:

$a_{33} = - 3 + (33 - 1) (4) = - 3 + 32 \times 4 = - 3 + 128 = 125$

Step 3. To find sum of first 20 terms.

$S_{20} = \frac{20}{2} {2 (- 3) + (20 - 1) 4} = 10 (- 6 + 19 (4)) = 10 (- 6 + 76) = 10 \times 70 = 700$

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.What is the 33rd term in the sequence $- 3, 1, 5, 9, . . . . . . . . . .$ ? What is the sum of the first 20 terms?

Short Answer

Step by step solution

Step 1. Given information

Step 2. To find 33rd term of the sequence.

Step 3. To find sum of first 20 terms.

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.What is the 33rd term in the sequence -3,1,5,9,..........? What is the sum of the first 20 terms?

Short Answer

Step by step solution

Step 1. Given information

Step 2. To find 33rd term of the sequence.

Step 3. To find sum of first 20 terms.

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Math Textbooks

Applied Mathematics

Theoretical and Mathematical Physics

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Study anywhere. Anytime. Across all devices.

.What is the 33rd term in the sequence $- 3, 1, 5, 9, . . . . . . . . . .$ ? What is the sum of the first 20 terms?