If `cos23^(@)=z`, find the value of `cos46^(@)` in terms of z.

Explanation

To find the value of \( \cos 46^\circ \) in terms of \( z \), where \( z = \cos 23^\circ \), we can use the double angle formula for cosine.

### Step-by-step Solution:

1. **Identify the relationship between angles**:
We know that \( 46^\circ \) is double of \( 23^\circ \):
\[
46^\circ = 2 \times 23^\circ
...