Consider \(\triangle ACB\), right-angled at \(C\), in which \(AB =17  \ \text{units}\), \(BC =15 \ \text{units}\) and \(\angle ABC = \theta\).
 
introduction to trigonometry session 1 ques1.png
 
Find the value of:
 
\(cos^2 \ \theta - sin^2 \ \theta =\) ii
 
(Note: Enter the answers without simplifying it)