# Need tips for this q (1 Viewer)

#### SummarisingHSC

##### New Member
I can't seem to think clearly for this q and the only option ic is expanding which is aids to say the least. Wuts a short quick method to use

#### ExtremelyBoredUser

##### hiiii
I can't seem to think clearly for this q and the only option ic is expanding which is aids to say the least. Wuts a short quick method to useView attachment 35997
This is just trig formula.

$\bg_white \cos(A)\cos(B) + \sin(A)\sin(B)= \cos(A-B)$
Hence it is
$\bg_white \cos(45 + x - 45 + x) = \cos(2x)$

#### SummarisingHSC

##### New Member
This is just trig formula.

$\bg_white \cos(A)\cos(B) + \sin(A)\sin(B)= \cos(A-B)$
Hence it is
$\bg_white \cos(45 + x - 45 + x) = \cos(2x)$
Bruh how did I not see that, thanks anyways appreciate it