Homework Help 10 points to whoever can help?

Question

I've spent about an hour and a half on this problem and i can't figure it out! Please help!


show that:

1/2*b*c*sinA= (a^2sin(2B)+b^2sin(2A))/4

were are suppose to show that the area of a triangle which is the first part equals the second part!

Answer 1

substitution...
lets say a=1 b=2 c=3...
1/2*2*3*sin(1) = (1^2*sin(2*2)+2^2*sin(2*1) /4
3*sin(1) = 1sin(4) + 4*sin(2) /4
=.0523572193 = .0523572193

im a genius :)

Answer 2

hi hmm...just been doing something rather similar also lately in maths.

try first of all expanding the inside brackets and then do the larger brackets.
tidy up the bracket after then divide by 4 and rearrange the answer so it looks like the first part.

This may be wrong so if u get it wrong then u know why, but hopefully this will help.