this is reaction engineering please show all steps

Davis et al studied the photocatalytic decomposition of wastewater dyes as a possible option for decolorization [R. J. Davis, J. L. Gainer, G. O'Neal, and L-W. Wu, Water Environ. Res. 66 (1994) 50]. The effluent from a municipal water treatment facility whose influent contained a high proportion of dyeing wastewater was mixed with Ti02 photocatalyst (0.40 wt. \%), sparged with air, and irradiated with UV light. The deep purple color of the original wastewater lightened with reaction time. Since the absolute concentration of dye was not known, the progress of the reaction was monitored colorimetrically by measuring the relative absorbance of the solution at various wavelengths. From the relative absorbance data collected at 438nm (shown below). Write out the integral for the rate expression for solving the rate constant k. The relative absorbance is the absorbance at any time t divided by the value at t=0 make sure you do include the integration range for the integration expression, and write out which is y, slope, and x for graphing on excel Additional information: 1) This decomposition reaction is assumed to be a first order reaction. 2) The relative absorbance is equivalent as cAcA Davis et al studied the photocatalytic decomposition of wastewater dyes as a possible option for decolorization [R. J. Davis, J. L. Gainer, G. O'Neal, and L-W. Wu, Water Environ. Res. 66 (1994) 50]. The effluent from a municipal water treatment facility whose influent contained a high proportion of dyeing wastewater was mixed with Ti02 photocatalyst (0.40 wt. \%), sparged with air, and irradiated with UV light. The deep purple color of the original wastewater lightened with reaction time. Since the absolute concentration of dye was not known, the progress of the reaction was monitored colorimetrically by measuring the relative absorbance of the solution at various wavelengths. From the relative absorbance data collected at 438nm (shown below). Write out the integral for the rate expression for solving the rate constant k. The relative absorbance is the absorbance at any time t divided by the value at t=0 make sure you do include the integration range for the integration expression, and write out which is y, slope, and x for graphing on excel Additional information: 1) This decomposition reaction is assumed to be a first order reaction. 2) The relative absorbance is equivalent as cAcA