Week 1 – My Arithmetic Sequence

5, 20, 35, 50, 65

To find the 50th term, use the formula: t_n = t_1 + (n – 1) d.

20 – 15 = 5

35 – 15 = 20

D= +15

t_{50} = 5 + (50 -1) ⋅ 15.

t_{50} = 5 + (49) ⋅ 15

t_{50} = 5 + 735

t_{50} = 740

Find S_{50} with the formula S_n\frac{n}{2} ( t_1 + t_n )

t_{50} =\frac{50}{2} ( 5 + 740)

t_{50} = 25 (745)

t_{50} = 18,625

 

 

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