Question

2sinx=?
pls give me ans

Answer 1

There are a plethora of formulae in Trigonometry. Most of them are derived from some standard formulae, and so is the formula of sin2x.

There is a formula of sin(A + B) = sin A cos B + cos A sin B.

Required formula: sin(2x); i.e. A=B in this case.

So we can rewrite it as sin(x+x).

or, sin(x+x) = sin x cos x + cos x sin x

or, sin2x = 2sinxcosx. [Ans]

So, this is how you can derive the formulae in trigonometry from the standard formula. Hope that helps. :)