prove that
Sin 20 sin 40 sin 80=√3/8
Answers
Answered by
2
Answer:
Sin(20)sin(40) = (1/2)[cos(20) - cos(60)]
=sin(20)sin(40)sin(80)
= (1/2)[cos(20) - cos(60)]sin(80)
= (1/2)[cos(20)sin(80) - cos(60)sin(80)]
= (1/2)[(1/2)(sin(100)+sin(60)) - (1/2)(sin(140)+sin(20))]
= (1/4)[sin(80) + sin(60) - sin(40) - sin(20)]
= (1/4)sin(60), since sin(80) - sin(40) - sin(20) = sin(60+20) - sin(60-20) - sin(20) = 2cos(60)sin(20) - sin(20) = 0
= √3/8
mark me as brainlist or follow me
Answered by
42
ʜʏ.
◆ your answer is giving attachment
ɪ ʜᴏᴘᴇ ɪᴛ's ʜᴇʟᴘ ᴜ... :)
◦•●◉✿THANK✿◉●•◦
ᴘʟᴢ ᴍᴀᴋᴇ ᴀ ʙʀᴀɪɴ ʟɪsᴛ ᴀɴsᴡᴇʀ
Attachments:
Similar questions