# SHM question

Faiq

## Homework Statement

Question is provided

## The Attempt at a Solution

The required solution is provided

My question is, the examiner have used sine theta in their expression for change in potential. I keep ending up with 1 - cosine theta
Second question is how did they get rid of theta in the proceeding equation

#### Attachments

• Inertia.jpg
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• Inertia answer.jpg
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## Answers and Replies

Mentor
See the left side. For small angles, ##\sin \theta \approx \theta## and ##\cos \theta \approx 1 - \frac 1 2 \theta^2## (sometimes ##\cos \theta \approx 1## is sufficient).