<s>[INST] Show that $2(\sin y + 1)(\cos y + 1) = (\sin y + \cos y + 1)^2$ The question states:

Show that: $$2(\sin y + 1)(\cos y + 1) = (\sin y + \cos y + 1)^2$$

This is what I have done 
$2(\sin y + 1)(\cos y + 1) = 2(\sin y + \cos y + 1)^2$
L. H. S.                = R. H. S.
From L. H. S.
$2(\sin y +1)(\cos y + 1) = 2(\sin y\cos y + \sin y + \cos y + 1)$
$= 2(\sin y\cos y + \sin y + \cos y + \sin^2 y + \cos^2 y)  (\sin^2 y + \cos^2 y = 1)$
$= 2(\sin^2 y + \sin y\cos y + \sin y + \cos^2 y + \cos y)$
I got stuck here. I do not know what to do from here. 
I have tried and tried several days even contacted friends but all to no avail.
 [/INST] $$\sin y=s,\cos y=c$$
$$(c+s+1)^2=c^2+s^2+1+2c+2s+2cs=2\underbrace{(1+c)}+2s\underbrace{(1+c)}=?$$
Another way
As $s^2+c^2=1$
$$(s+(c+1))^2=s^2+(c+1)^2+2s(c+1)=1-c^2+(c+1)^2+2s(c+1)=(c+1)[1-c+c+1+2s]=?$$
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