Question

using the formula cos square A equal to 2 cos square A-1 find the value of cos 30 degree it is being given that Cos 60 degree is equal to 1/2​

Answer 1

Answer:

Step-by-step explanation:

given cos60=1/2

we have the following equation

cos square A= cossquare 2A -1

putting A=30

we get cos square 30 =cos square 30*2 -1

cos square 30 = cos square 60 -1

cos 30 =root of 1/4-1

cos 30 = root of -3/4

cos 30 =root 3 /4

by the way the question is somewhat incorrect

In RHS it should be 1-cos suare 2A