Question

prove this cos (65°+A).cos (35°+A) + sin( 65°+A). sin(35°+A)=√3/2​

Answer 1

Hi friend!!

We know that

CosACosB+sinAsinB=cos(A-B)

Given,

cos (65°+A).cos (35°+A) + sin( 65°+A). sin(35°+A)=√3/2

cos(65+A-35-A)=√3/2

cos(30)=√3/2

√3/2=√3/2

L.H.S=R.H.S

hence proved!

I hope this will help you;)

Answer 2

Answer:

√3/2

Step-by-step explanation:

By applying the formula ( cos (A-B))

• cos (65+theta-35-theta)
• cos 30°
• √3/2