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Q 61.

Expert-verified
Found in: Page 809

### Precalculus Enhanced with Graphing Utilities

Book edition 6th
Author(s) Sullivan
Pages 1200 pages
ISBN 9780321795465

# In Problems 61–70, express each sum using summation notation.$1+2+3+...+20$

The required summation notation is $1+2+3+...+20=\sum _{k=1}^{20}k$.

See the step by step solution

## Step 1. Write the given information.

The given sum is:

$1+2+3+...+20$

## Step 2. Write the summation notation of the sum.

As we can see that the sum $1+2+3+...+20$ has 20 terms, each term represents the form $k$, and starts at $k=1$ and ends at $k=20$.

Therefore, $1+2+3+...+20=\sum _{k=1}^{20}k$.