Question

sinxcosy = 1/2 (sin(x+y) + cos(x-y))
True or False?

Answer 1

sin(x+y) = sin(x)cos(y) + sin(y)cos(x)

cos(x-y) = cos(x)cos(y) + sin(x)sin(y)

can do you it now ?

Answer 2

er true?

Answer 3

\[\sin(x+y) = \sin(x) \cos(y) + \cos(x) \sin(y)\]
\[\cos(x-y) = \cos(x) \cos(y) + \sin(x) \sin(y)\]

Answer 4

Can you add now \(sin(x+y)\) and \(cos(x-y)\) ??

Answer 5

huh?

Answer 6

its (sin(x+y)) + (cos(x-y)) ._.

Answer 7

I said add expansion that we have given there above..

Add the expansion of sin(x+y) and cos(x-y) and tell me what did you get ??

Answer 8

i just told you what "I" can get

Answer 9

using :
sin(x+y) = sin(x)cos(y) + sin(y)cos(x)

cos(x-y) = cos(x)cos(y) + sin(x)sin(y)
your equation becomes
sinxcosy = 1/2 (sin(x)cos(y) + sin(y)cos(x) + cos(x)cos(y) + sin(x)sin(y))

Answer 10

so ....true then

Answer 11

no false
bc thats sin x cos y = sinx cosy
...wait ..waht?

Answer 12

show me

Answer 13

Wow! @Mpost knows how to show off but is neither elegant in his writing nor can he solve such simple simple questions. It seems like the only thing he does know is how to be disrespectful towards authority figures. Needs serious counselling. Almost feel sorry for this arrogant sorry excuse for a human.

Answer 14

It is wrong...

Answer 15

\[\rm 2\sin(x)\cos(y) \ne \sin(x)\cos(y) + \sin(y)\cos(x) + \sin(x)\sin(y) + \cos(x)\cos(y)\]