Giving an arithmetic sequence with a33=66 and a common difference of 2.

Question

Giving an arithmetic sequence with a33=66 and a common difference of 2.

Find a1;

Hint: Use an = a1 + (n-1) d

a1= ___________

Find the sum of the first 30 terms:

Hint: Use an = a1 + (n-1) d and Sn = n/2 (a1 + an)

S30 = __________

Answer 1

a₃₃ = a₁ + 32d

66 = a₁ + 32(2)

Can you solve for a₁ and answer?

S₃₀ = (30/2)(2a₁ + 29(2), use a₁ from above

Both of these are standard formulas with which you should be familiar.