Evaluate the following.
sin 25° sin 65° – cos 25° cos 65°.
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 0
Formula used
Cos (A + B) = Cos A Cos B - Sin A Sin B
Calculation
sin 25° sin 65° – cos 25° cos 65°
- Cos(25 + 65) = - Cos 90º = 0