Question

i pavoue !yang that (cosnt cosyl ² + (sin na siny) - 4 cas? ਕ​

Answer 1

Answer:

LHS=cos  

2

A+cos  

2

B+2cosAcosB+sin  

2

A+sin  

2

B−2sinAsinB

(cos  

2

A+sin  

2

A)+(cos  

2

B+sin  

2

B)+2cosAcosB−2sinAsinB

2+2cosAcosB−2sinAsinB

2+cos(A+B)+cos(A−B)−cos(A−B)+cos(A+B)

2+2cos(A+B)          (∴cosx=2cos  

2

 

2

x

​

−1)

2+2[2cos  

2

 

2

(A+B)

​

−1]

2+4cos  

2

 

2

(A+B)

​

−2=4cos  

2

 

2

(A+B)

​

=R.H.S

Hence proved.

Step-by-step explanation: