# I Integration of Sin(x)

1. Mar 5, 2016

### Karim Habashy

Hi All,

This is a very elementary question but, from calculus :

∫sinx dx from 0 to pi = 2, but i thought of it, in terms of the attached driagram.

And if we think of it, this way, the integration is the area of a half circle of radius one and is equal to Pi/2.

Where did i go wrong ?

2. Mar 5, 2016

### blue_leaf77

No, it's not. Your mistake was to assume $x$ as the coordinate in the horizontal line, when it's actually the angle subtended between the line and the horizontal axis.

3. Mar 5, 2016

### Karim Habashy

You are right, thanks. the integration would be ∫(sinx)2 dx which is Pi/2.