Prove that:`cos^2(pi/4-theta)-sin^2(pi/4-theta)=s in2theta`

Explanation

To prove that \( \cos^2\left(\frac{\pi}{4} - \theta\right) - \sin^2\left(\frac{\pi}{4} - \theta\right) = \sin(2\theta) \), we can follow these steps:

### Step 1: Use the identity for the difference of squares
We know that:
\[ \cos^2 x - \sin^2 x = \cos(2x) \]
In our case, let \( x = \frac{\pi}{4} - \theta \). Therefore, we can rewrite the left-hand side (LHS) as:
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