Can anyone remember the proofs of these Identities?
Sin(a+b) = Cos(a)Sin(b) + Sin(a)Cos(b)
Cos(a+b) = Cos(a)Cos(b) - Sin(a)Sin(b)
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Can anyone remember the proofs of these Identities?
Sin(a+b) = Cos(a)Sin(b) + Sin(a)Cos(b)
Cos(a+b) = Cos(a)Cos(b) - Sin(a)Sin(b)
First, I thought of answering this, but then, I saw this page
http://mathforum.org/dr.math/problems/susan5.16.98.html
and they have done a good job..so I am off. :)
This question reminds me of how old i am....
sin(A + B)
sin A = cos(pi/2 - A)
sin (A + B) = cos(pi/2 - (A + B))
sin(A + B) = cos ((pi/2 - A) - B)
sin(A + B) = cos(pi/2 - A)cosB + sin(pi/2 - A)sinB
sin(A + B) = sinAcosB + cosAsinB
http://users.erols.com/bram/identities.html