Math, asked by nepali8, 2 months ago

express 2sin61°*sin39° as sum or difference form​

Answers

Answered by veerajagarwal
0

Answer:

Consider the equation,

Case 1- 2sin4θcos2θ

sinA+sinB=2sin(

2

A+B

)cos(

2

A−B

)

=2sin(

2

6θ+2θ

)cos(

2

6θ−2θ

)

=2sin4θcos2θ

Case 2- 2sin2θcos4θ

sinA+sinB=2sin(

2

A+B

)cos(

2

A−B

)

=2cos(

2

6θ+2θ

)sin(

2

6θ−2θ

)

Case 3- 2sin2θsin4θ

cosA−cosB=−2sin(

2

A+B

)sin(

2

A−B

)

=−2sin(

2

6θ+4θ

)sin(

2

6θ−2θ

)

=2sin2θsin4θ

Case 4-2cos2θcos4θ

cosA−cosB=2cos(

2

A+B

)cos(

2

A−B

)

=2cos(

2

6θ+4θ

)cos(

2

6θ−4θ

)

=2cos2θcos4θ

Hence, Proved.

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