Question Detail
Question
The value of cos 15° using surds is:
Correct Answer
Option C is the correct answer.
Detailed Explanation
cos 15° = cos (45°-30°) = cos 45° cos 30° + sin 45° sin 30° = (√2/2)(√3/2) + (√2/2)(1/2) = (√6/4) + (√2/4) = (√6+√2)/4.
Hint
The notes indicate answer C.