prove that tan20 .tan40.tan80=tan60.
Answers
Answered by
7
tan40.tan20.tan80 = tan60
Taking L.H.S.
tan40.tan80.tan20
=(sin40 sin80)sin20/cos40 cos80(cos20)
=(2sin40 sin80) sin20 / (2cos40 cos80)cos20
=(cos40- cos120) sin20 / (cos120 + cos40) cos20
=(2cos40 + 1)sin20 / (2cos40 - 1) cos20
=2cos40sin20 + sin20 / 2cos40cos20 - cos20
=sin60 - sin20 + sin20 / cos60 + cos20 - cos20
=sin60/cos60
=tan60 = R.H.S.
Cheers .
Answered by
2
Answer:
Step-by-step explanation:
vhh
Attachments:
Similar questions