If 0 < f ≤ 90 and cos(22f − 1) = sin(7f + 4), what is the value of f?

3

Step-by-step explanation:

We are going to be using cofunction identity cos(90-x)=sin(x).

Apply to either side but not both.

cos(22f − 1) = sin(7f + 4)

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

90-[22f-1]=7f+4

Distribute

90-22f+1=7f+4

Combine like terms

91-22f=7f+4

Add 22f on both sides

91=29f+4

Subtract 4 on both sides

87=29f

Divide 29 on both sides

3=f

f=3 is between 0 and 90

9 x 8 divided by (5-3)=36