1. space space space F i n d space theta element of open square brackets table row cell 0 space comma end cell cell pi over 2 end cell end table close square brackets space r e p r e s e n t i n g space t h e space s o l u t i o n space o f space
space space space space space space space space space space open vertical bar table row cell 1 plus cos squared theta end cell cell sin squared theta end cell cell 4 sin 4 theta end cell row cell cos squared theta end cell cell 1 plus sin squared theta end cell cell 4 sin 4 theta end cell row cell cos squared theta end cell cell sin squared theta end cell cell 1 plus 4 sin 4 theta end cell end table close vertical bar equals 0


2. space space space i f space a comma b comma c space a r e space s u c h space t h a t space a plus b plus c equals 0
p r o v e space t h a t
open vertical bar table row 1 cell cos c end cell cell cos b end cell row cell cos c end cell 1 cell cos a end cell row cell cos b end cell cell cos a end cell 1 end table close vertical bar

Asked by Eng.surinder.singh | 25th Jan, 2019, 01:06: PM

Expert Answer:

only one question is answered per posting. First question is answered
 
After expanding the determinant, the resulting expression is simplified to get solution for θ as given below
 

Answered by Thiyagarajan K | 26th Jan, 2019, 03:11: PM

Queries asked on Sunday & after 7pm from Monday to Saturday will be answered after 12pm the next working day.