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Find the sum.

sum_(k=1)^(50)(5k-161)=

Find the sum.\newlinek=150(5k161)= \sum_{k=1}^{50}(5 k-161)=

Full solution

Q. Find the sum.\newlinek=150(5k161)= \sum_{k=1}^{50}(5 k-161)=
  1. Find First Term: We need to find the sum of the arithmetic series given by the expression 5k1615k-161 from k=1k=1 to 5050. The sum of an arithmetic series can be found using the formula S=n2×(a1+an)S = \frac{n}{2} \times (a_1 + a_n), where nn is the number of terms, a1a_1 is the first term, and ana_n is the last term.
  2. Calculate Last Term: First, we calculate the first term of the series when k=1k=1. The first term a1a_1 is given by the expression (5k161)(5k-161) when k=1k=1, which is (5×1161)=5161=156(5\times 1-161) = 5-161 = -156.
  3. Apply Sum Formula: Next, we calculate the last term of the series when k=50k=50. The last term ana_n is given by the expression (5k161)(5k-161) when k=50k=50, which is (5×50161)=250161=89(5\times 50-161) = 250-161 = 89.
  4. Calculate Sum: Now we have the first term a1=156a_1 = -156 and the last term an=89a_n = 89. We also know the number of terms n=50n = 50. We can now use the sum formula for an arithmetic series: S=n2×(a1+an)S = \frac{n}{2} \times (a_1 + a_n).
  5. Calculate Sum: Now we have the first term a1=156a_1 = -156 and the last term an=89a_n = 89. We also know the number of terms n=50n = 50. We can now use the sum formula for an arithmetic series: S=n2×(a1+an)S = \frac{n}{2} \times (a_1 + a_n). Plugging the values into the formula, we get S=502×(156+89)=25×(67)=1675S = \frac{50}{2} \times (-156 + 89) = 25 \times (-67) = -1675.

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