#4: 2a) ANSWER: Þ 2 ( 2 cos 2 0 + 3 sin 2 0 - 4 cos 2 ø
) + Þ sinø cos0 = 5
SOLUTION: 2( Þ sinø cos0 ) 2 + 3( Þ sinø
sin0 ) 2 - 4( Þ cosø ) 2 + ( Þ sinø cos0 )
= 5
Þ 2 ( 2 cos 2 0 + 3 sin 2 0 - 4 cos 2 ø ) + Þ
sinø cos0 = 5
#4: 2c) ANSWER: Þ = 8 / (sinø cos0 + 2 sinø
sin0 + 3 cosø )
SOLUTION: Þ sinø cos0 + 2Þ sinø
sin0 + 3Þ cosø = 8 or Þ = 8 / (sinø
cos0 + 2 sinø sin0 + 3 cosø )
#4: 2e) ANSWER: ø = + pi / 4
SOLUTION: ( Þ sinø cos0 ) 2 + ( Þ sinø
sin0 ) 2 - ( Þ cosø ) 2 = 0 or
sin 2 ø cos 2 0 + sin 2 ø sin 2 0 - cos 2 ø = 0 or
sin 2 ø = cos 2 ø or tan ø = + 1 or ø = + pi / 4