Question

Find the value of sin50 x cos 40 + cos 50 x sin 40

Answer 1

sin50 x cos 40 + cos 50 x sin 40
= sin(50+40)
= sin 90
= 1

Answer 2

= sin(50) * cos(90-50) + cos(50) * sin(90-50)
= sin(50)*sin(50) + cos(50)*cos(50)
=sin²(50) + cos²(50) 
= 1