Question 1202034
If 0 < f ≤ 90 and cos(22f − 1) = sin(7f + 4), 
angle in quadrant I

Cos {{{theta}}}= sin(90-{{{theta)}}}  (complementary angles )

= sin (90-(22f-1)) = sin (7f+4)

Comparing both sides of the equation

90-22f+1 = 7f+4

90+1-4 =22f+7f

87= 29f
f=3