Question

Please answer it fast... ​

Answer 1

Answer:

sin(90-a)*cos(90-a)=2cos(a)sin(a)/2

= sin(2a)/2

= (2tana/(1+tan^2))*1/2

= tana/(1+tan^2a)

Answer 2

Step-by-step explanation:

LHS:-

sin(90°-A) cos(90°-A)

= (cos A) (sin A)

RHS:-

$\frac{tan \: a}{1 + {tan}^{2} \: a }$

$= \frac{ \frac{sin \: a}{cos \: a} }{ {sec}^{2} }$

$= \frac{ \frac{sin \: a}{cos \: a} }{ \frac{1}{ {cos}^{2} \: a } }$

$= \frac{sin \: a}{cos \: a} \times {cos}^{2} \: a$

$= (sin \: a) \: (cos \: a)$

'Cause

LHS = RHS

Hence,

itvs proved

Please mark the answer as brainliest..