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| Question 44039This question is from textbook
 :  Please help me solve the following problems. I've tried to solve the problem  but I don't it correct.
 1) Use the arithmetic sequence of numbers 1, 3, 5, 7, 9,…to find the following:
 a)What is d, the difference between any 2 terms?
 Answer:
 d = 2
 Show work in this space.
 3-1=2
 5-3=2
 b)Using the formula for the nth term of an arithmetic sequence, what is 101st term?
 Answer:
 an = 1 + (n - 1)2
 
 Show work in this space.
 
 c)Using the formula for the sum of an arithmetic series, what is the sum of the first 20 terms?
 Answer:
 Sum a20 = 400
 Show work in this space
 Sum an = n[2a1 + (n - 1)d] / 2
 Sum a20 = 20[2 + (20 - 1)2] / 2
 Sum a20 = 10[2 + (20 - 1)2]
 Sum a20 = 10[2 + (19)2]
 Sum a20 = 10[2 + 38]
 Sum a20 = 10[40]
 Sum a20 = 400
 
 
 d)Using the formula for the sum of an arithmetic series, what is the sum of the first 30 terms?
 Answer:
 
 Sum a20 = 900
 
 Show work in this space
 Sum an = n[2a1 + (n - 1)d] / 2
 Sum a20 = 30[2 + (30 - 1)2] / 2
 Sum a20 = 15[2 + (30 - 1)2]
 Sum a20 = 15[2 + (29)2]
 Sum a20 = 15[2 + 58]
 Sum a20 = 15[60]
 Sum a20 = 900
 
 
 e)What observation can you make about these sums of this series (HINT: It would be beneficial to find a few more sums like the sum of the first 2, then the first 3, etc.)?  Express your observations as a general formula in "n."
 Answer:
 
 N	an	Sum
 1	1
 2	3	4
 3	5	9
 4	7	16
 5	9	25
 6	11	36
 7	13	49
 8	15	64
 9	17	81
 The sum of the nth in the series is the square of n. 
This question is from textbook
 
 Answer by venugopalramana(3286)
      (Show Source): 
You can put this solution on YOUR website! SEE MY COMMENTS BELOW Please help me solve the following problems. I've tried to solve the problem but I don't it correct.
 1) Use the arithmetic sequence of numbers 1, 3, 5, 7, 9,…to find the following:
 a)What is d, the difference between any 2 terms?
 Answer:
 d = 2....CORRECT
 Show work in this space.
 3-1=2.......7-5=9-7=2...C.D.IS CONSTANT =2..HENCE A.P.
 5-3=2
 b)Using the formula for the nth term of an arithmetic sequence, what is 101st term?
 Answer:
 an = 1 + (n - 1)2
 Show work in this space.
 A101=1+(101-1)*2=1+200=201
 c)Using the formula for the sum of an arithmetic series, what is the sum of the first 20 terms?
 Answer:
 Sum a20 = 400..........PERFECT..
 Show work in this space
 Sum an = n[2a1 + (n - 1)d] / 2
 Sum a20 = 20[2 + (20 - 1)2] / 2
 Sum a20 = 10[2 + (20 - 1)2]
 Sum a20 = 10[2 + (19)2]
 Sum a20 = 10[2 + 38]
 Sum a20 = 10[40]
 Sum a20 = 400
 
 d)Using the formula for the sum of an arithmetic series, what is the sum of the first 30 terms?
 Answer:
 Sum a20 = 900..................EXCELLENT
 Show work in this space
 Sum an = n[2a1 + (n - 1)d] / 2
 Sum a20 = 30[2 + (30 - 1)2] / 2
 Sum a20 = 15[2 + (30 - 1)2]
 Sum a20 = 15[2 + (29)2]
 Sum a20 = 15[2 + 58]
 Sum a20 = 15[60]
 Sum a20 = 900
 
 e)What observation can you make about these sums of this series (HINT: It would be beneficial to find a few more sums like the sum of the first 2, then the first 3, etc.)? Express your observations as a general formula in "n."
 Answer:
 N an Sum
 1 1
 2 3 4
 3 5 9
 4 7 16
 5 9 25
 6 11 36
 7 13 49
 8 15 64
 9 17 81
 The sum of the nth in the series is the square of n. OUTSTANDING!!!
 YOU DID OUTSTANDING JOB..WHY ARE YOU HAVING DOUBT!!BE CONFIDENT
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