wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

Show that sin4π8+sin43π8+sin45π8+sin47π8=32

Open in App
Solution

sin4π8+sin43π8+sin45π8+sin47π8

=[sin2π8]2+[sin23π8]2+[sin25π8]2+[sin27π8]2

=[1cosπ42]2+1cos3π422+1cos5π422+1cos7π422

=11222+1+1222+1+1222+11222

=18[(442+2)+(4+42+2)]

=128

=32

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon