### Single Variable Calculus: Early Tr...

8th Edition
James Stewart
Publisher: Cengage Learning
ISBN: 9781305270336

Chapter
Section

### Single Variable Calculus: Early Tr...

8th Edition
James Stewart
Publisher: Cengage Learning
ISBN: 9781305270336
Chapter E, Problem 36E
Textbook Problem
1 views

## Find the number n such that ∑ i = 1 n i = 78 .

To determine

To find: The number n such that i=1ni=78.

### Explanation of Solution

Theorem used:

Let c be a constant and n be a positive integer. Then,

i=1nc=nc, i=1ni=n(n+1)2 and i=1ni2=n(n+1)(2n+1)6.

Calculation:

By the above theorem, it is given that i=1ni=n(n+1)2.

Thus, the expression i=1ni=78 simplified as, n(n+1)2=78.

Solve the equation n(n+1)2=78 and obtain the value of n.

n(n+1)2=78n(n+1)=156n2+n156=0

The equation n2+n156=0 is a quadratic equation with variable n

### Still sussing out bartleby?

Check out a sample textbook solution.

See a sample solution

#### The Solution to Your Study Problems

Bartleby provides explanations to thousands of textbook problems written by our experts, many with advanced degrees!

Get Started

Find more solutions based on key concepts