What is the function of voltage divider in the below circuit?
The opamps work with single supply only. 

That means: To allow the output to swing above and below the quiescent value this quiescent dc value at the output must be somewhere in the middle between the limits (set by ground potential and Vcc). Hence, the input is biased with 50% of Vcc. This dc voltage is transferred to the output of the opamps because the DC gain is unity (caused by the capacitors C1 and c2). The second opamp does not need a separate bias voltage divider because it is dc coupled to the output of the first opamp.