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Summation Notation (Σ)
★★☆☆☆Middle School
📖Definition
Σ (sigma) is a symbol for expressing sums of consecutive terms concisely. Lower index below, upper index above.
📐Formulas
∑_i=1ⁿ aᵢ = a₁ + a₂ + ... + aₙ
Summation definition
∑_i=1ⁿ c · aᵢ = c ∑_i=1ⁿ aᵢ
Constant factor
∑_i=1ⁿ (aᵢ + bᵢ) = ∑_i=1ⁿ aᵢ + ∑_i=1ⁿ bᵢ
Sum distribution
✏️Examples
예제 1
Calculate Σᵢ₌₁⁵ i².
예제 2
Σᵢ₌₁ⁿ i = ?
⚡Applications
Statistics
Mean, variance calculation
Sequences
Series sums
Programming
Loop representation
#시그마#합#summation#sigma