determine the exact value of cos(121) cos(59) - sin(121) x sin(59)

Answer 1

We can use the identity:
cos(A - B) = cos(A)cos(B) + sin(A)sin(B)

Let A = 121 and B = 59.

Therefore, cos(121 - 59) = cos(121)cos(59) + sin(121)sin(59)

cos(62) = cos(121)cos(59) + sin(121)sin(59)

Since cos(62) is an exact value, we have:

cos(121)cos(59) + sin(121)sin(59) = cos(62)

Therefore, the exact value of cos(121)cos(59) - sin(121)sin(59) is cos(62).

Answer 2

cos(121) cos(59) - sin(121) sin(59) = cos(121+59) = cos(180) = -1

Answer 3

My apologies for the mistake. You are correct.

cos(121) cos(59) - sin(121) sin(59) = cos(180) = -1