MAJOR HELP PLEASE!!
Verify that the equation is an identity. Show all your work.

(sin x + cos x)^2 - 1 = sin 2x

Question

MAJOR HELP PLEASE!!
Verify that the equation is an identity. Show all your work.

(sin x + cos x)^2 - 1 = sin 2x

nubeer · Answer

(a+b)^2 =a^2+2ab+b^2
so
(sin x + cos x)^2 - 1
sin^2x+2sinxcosx+cos^2x -1
2sinxcosx +sin^2x+cos^2x -1
i think u can do from here.

tamtoan · Answer

use formula $$(a+b)^{2} = a^{2} + 2ab + b^{2}$$, expand that out and you will see what you need to

anonymous · Answer

@nubeer i'm sorry i am a little lost, could you please explain further?

nubeer · Answer

2sinxcosx +sin^2x+cos^2x -1
have you understood how i have got this part?

anonymous · Answer

yes with the formula right?

nubeer · Answer

2sinxcosx +sin^2x+cos^2x -1
what is sin^2x+cos^2x = ?

anonymous · Answer

1?

nubeer · Answer

yes.. now put this 1 in the equation
2sinxcosx +sin^2x+cos^2x -1
2sinxcosx +1-1.. got it?

nubeer · Answer

@kenneyfamily  so?

anonymous · Answer

2sinxcosx

anonymous · Answer

@nubeer right?

nubeer · Answer

yes 
and 2sinxcosx=sin2x (according to the identity)

anonymous · Answer

you're awesome..thanks!!!