A question includes logarithm and trigonometry. Could anybody help me to solve this, please?

Condense the logarithms on the left side:

Recall the double angle identity for sine, :

Write both sides as powers of 2:

Simplify this:

Solve for :

(where is any integer)

Recall that :

Solve for :

We get solutions in the interval when , giving

a28=58

step-by-step explanation:

a1=a1+(n-1)d

a28= 4+ (28-1)2

a28=4+(27)(2)

a28=4+54

a28=58