Question

Use the sum formula for sine to prove the double angle formula for sine?

Answer 1

is this the sum formula ?
sin (a + b ) = sin a cos b + cos a sin b

Answer 2

Yes m'am

Answer 3

sin(2a)=sin(a+a)
=sinacosa + cosasina
=sinacosa + sinacosa
=sinacosa(2)
=2sinacosa

Answer 4

let a + b =p
let a-b =q
sin(a + b) + sin (a-b)
2a = p + q a = (p + q)/2
subtract b -(-b) = 2b = (p-q)/2

Answer 5

@babydollBET would you like me to continue?

Answer 6

No I've got it now thank you @triciaal

Answer 7

ok