Question

evaluate cos75° without using calculator​

Answer 1

*Question:-

• Evaluate cos75° without using calculator.

*Answer:-

We can write Cos(75) = Cos(45+30)

Using formula,

Cos(A+B) = Cos(A)*Cos(B) - Sin(A)*Sin(B)

We can write

Cos(75) = Cos(45+30)

= Cos(45)*Cos(30) - Sin(45)*Sin(30)

= (1/√2)*(√3/2) - (1/√2)*(1/2)

= (√3–1)/2*√2

Hope it helps you.