Answer:
-1/√2
Step-by-step explanation:
According to trigonometry identity
cos(A+B) = cosAcosB - sinA sinB
Given the expression
(cos92°)(cos133°)-(sin92°)(sin133°)
This can be expressed as cos(92+133) where A = 92, B = 133
(cos92°)(cos133°)-(sin92°)(sin133°)
= cos(92+133)
= cos225
= -0.7071
= -1/√2
Hence the exact value is -1/√2
