Question

If
$\sin( \alpha + \beta ) = 1$ then
$\cos( \alpha - \beta )$
can be reduced to​

Answer 1

HEY MATE YOUR ANSWER IS HERE...

$\sin( \alpha + \beta ) = 1$

$\sin90 = 1$

HENCE ,

$\sin( \alpha + \beta ) = \sin(90)$

HENCE

$\alpha + \beta = 90$

$\alpha = 90 - \beta$

$so \: let \: \alpha = 60 \: and \: \beta = 30$

$(as \: \alpha > \beta )$

NOW ,

$\cos( \alpha - \beta )$

$= cos (60 - 30)$

$\cos30$

$= \frac{ \sqrt{3} }{2}$

HOPE IT HELPS THANKS FOR YOUR QUESTION!!

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