Question

Need help with this ASAP

Answer 1

The answer is,

`√(3)/2`

Explanation:

Since we have cos10cos20 - sin10sin20,

We can use the formula,

cos(a+b) = (cosa)(cosb) - (sina)(sinb)

So, we have,

cos10cos20 - sin10sin20 = cos(10 + 20)

= cos(30)

cos(30) = sqrt(3)/2

`cos(30) = √(3)/2`