Question

given : sin (2A + 3B) = 1/3 and cos (2A - 3B) = 2^sqrt2/3, the value of sin 4A =...?

Answer 1

what do you think?

Answer 2

i am confuse...

Answer 3

@tblue1998 can we write
sin(4A) as sin [ {2A +3B} + {2A -3B} ]
now we can apply sin(X+Y)= sinX*cosY + cosX*sinY

Answer 4

is all well? @tblue1998

Answer 5

yeah, thanks

Answer 6

@niksva but, how to get the value of cos(2A+3B) ?

Answer 7

use
\[\sin^2(x) + \cos^2(x) = 1\]

Answer 8

oh, you really help me...