Question

How do you verify sinθcosθtanθ+cos2θ=1?

Answer 1

I am writing theta as x

$\sin(x) \cos(x) \tan(x) + { \cos(x) }^{2}$

$\sin(x) \cos(x ) \times \frac{ \sin(x) }{ \cos(x) } + { \cos(x) }^{2}$

$\sin(x) \times \sin(x) + { \cos(x) }^{2}$

${ \sin(x) }^{2} + { \cos(x) }^{2}$

Since sin^2 a+ cos^2 a= 1

$= 1 = rhs$