Question

Am I correct on these? I selected two answers as true, but I'm not sure if there's a third true answer provided.

Answer 1

I know the second option is false, but what about the third statement, C?

Answer 2

it is also true :)

Answer 3

third statement is true as well

Answer 4

try it out yourself, prove it works

Answer 5

Okay, awesome! Thank you guys (: I wasn't sure, in my text book it said that it can be derived from sum identities but didn't say anything about (A + A) or (A + B)

Answer 6

it happens like this, sin(a+b)=sinacosb+cosasinb
put b=a, so sin(a+a)=sinacosa+sinacosa
sin2a=2sinacosa

Answer 7

OOH! That makes sense (: Lol

Answer 8

and for cos2a, try yourself :)

Answer 9

Okie dokie (: Thank you for the help and pointers! :D