COMEDK 2024 Shift 2 Paper

We can find the value of cos‌105∘ using the angle subtraction formula:
cos(A−B)=cos‌A‌cos‌B+sin‌A‌sin‌B
Let's write 105∘ as the difference of two angles whose cosine and sine values we know:
105∘=135∘−30∘
Now, we can apply the angle subtraction formula:
We know that:
Substituting these values, we get:
Combining the terms, we get:
cos‌105∘=−‌

(√3−1)

2√2

Therefore, the correct option is Option B.