In O Level, students are taught that

So naturally, students may think that (a is a constant)

Well, actually that is good pattern spotting, but unfortunately it is **incorrect**. Do not be too disheartened if you make this mistake, it is a **common mistake**.

The above is a **conceptual error** as **only holds when n is a constant**.

Fortunately, this question is rarely tested, though it is quite possible that **it can come up in A Levels**.

To fully understand the following steps, it would help** read my other post (Why is e^(ln x)=x?) first**.

First, we write .

Hence

After **fully understanding the above steps**, you may **memorize the formula** if you wish:

**Memory Tip**: **If you let a=e**, you should get

The above steps involve the **chain rule**, which I will cover in a subsequent post.

### Like this:

Like Loading...

*Related*

wow nice tutorial , good technique 🙂 , I’m learning thanks 🙂

LikeLike