velox
Retired
Wrong answers for most of these...
8. Find the 7th term of the arithmetic progression whose 5th term is m and whose 11th term is n.
16. Find the sum of all integers between 20 and 50 that are divisible by 3.
17. A body, falling freely from a height, travels 4.9 metres in the first second, 14.7m in the second second and 24.5m in the third. How far has it fallen after 6s?
I tried using the 'sum to n terms' formula but that yielded the incorrect answer of 205.8m unless i haven't realised my mistake. Then i tried using the term formula (tn = a + (n - 1)d) for the 6 individual terms, and then added them up, and that worked. Any reason why the sum didnt work properly?
20. Show that the sum of the first n odd natural numbers is a perfect square.
22. The third term equals -2. The 9th term equals 28. How many terms of this arithmetic sequence, beginning with the first term are required to give this a sum of 1092?
Thanks guys
8. Find the 7th term of the arithmetic progression whose 5th term is m and whose 11th term is n.
16. Find the sum of all integers between 20 and 50 that are divisible by 3.
17. A body, falling freely from a height, travels 4.9 metres in the first second, 14.7m in the second second and 24.5m in the third. How far has it fallen after 6s?
I tried using the 'sum to n terms' formula but that yielded the incorrect answer of 205.8m unless i haven't realised my mistake. Then i tried using the term formula (tn = a + (n - 1)d) for the 6 individual terms, and then added them up, and that worked. Any reason why the sum didnt work properly?
20. Show that the sum of the first n odd natural numbers is a perfect square.
22. The third term equals -2. The 9th term equals 28. How many terms of this arithmetic sequence, beginning with the first term are required to give this a sum of 1092?
Thanks guys