Question

How would you verify the trigonometric identity 2x = 2sinx cosx

Answer 1

Explanation:

2x = 2sinx cosx is not an identity. An identity is "always true," whereas a conditional equation is true only for specific value(s) of the unknown. Double check to ensure that you have copied down this problem correctly.

Answer 2

Explanation:

Hi, there!!

I hope you mean sin2x=2sinx . cosx

so, let's begin in a simple way; by adding, alright:

sin2x= sin(x+x) (as 2x=x+x).

now, let's use compound formula for sin,

so, we get:

sin (x+x)= sinx.cosx + cosx. sinx (as sin(A+B)=sin A. cosB + cosA . sinB)

or, sin (x+x)=2sinx.cosx (adding both).

Therefore, sin 2x = 2sinx. cosx.

Hope it helps..