Answer:
Ans: 0.766
Step-by-step explanation:
Use the trig identity: cos (a + b) = cos a,cos b - sin a.sin b
cos (25 + 15) = cos (40) = cos 25.cos 15 - sin 25.sin 15.
The arc
40
∘
doesn't have exact functional value.
You may get its approx. value by calculator.
cos 40 = 0,766
