Question

Plzzzzzzzzzzzz solve Q 5

Answer 1

Question : Find the value of sin( 60 + A ) - cos( 30 - A )

Theta is written as A .



solution :

→ sin( 60 + A ) - cos( 30 - A )


we know, cos( 90 - ∅ ) = sin∅ and vice versa.

changing sin( 90 + A ) in terms of cos according to the formula given above.


→ cos{ 90 - ( 60 + A ) } - cos( 30 - A )

→ cos( 90 - 60 - A ) - cos( 30 - A )

→ cos( 30 - A ) - cos( 30 - A )



As both are same with different signs, there sum will be 0


→ 0



Answer : 0


$\:$

Answer 2

Given,

$\sin(60+\theta)-\cos(30-\theta)\\\;\\=\sin(60+\theta)-\sin[90-(30-\theta)]\\\;\\=\sin(60+\theta)-\sin(90-30+\theta)\\\;\\=\sin(60+\theta)-\sin(60+\theta)\\\;\\=0\\\;\\\;\\Note:\;\;\cos\theta=\sin(90-\theta)$