Question

Sin2a=2sinacosa find a

Answer 1

sin(2A) = sin(A + A)
As sin(a + b) = sinacosb + sinbcosa,
sin(A + A) = sinAcosA + sinAcosA
Therefore sin(2A) = 2sinAcosA

How can 'a' be found when it is with angle. This is a derived formula

Answer 2

heya folk!!!

let a linear pair AB line
at which two angle <a and <b
but <a=<b.-------1)(given)

so we can say that ,

<a+<b=180°【linear pair】
<a+<a=180°
<a=90°----------2)

now,from lhs .
sin2a
=)sin2*90°

=)sin180°=0.

again from Rhs..
2sina*cosa
=)2sin90°*cos90°

=)2*0*1

=0 ..

hence here lhs =Rhs are prooved ..

so we can say that <a=90°[from linear pair】

hope it help you.☺

@rajukumar☺