α^n,m(c)=12⁢π⁢∫02⁢πcos⁡t⁢cen⁡(t,h2)⁢cem⁡(t,h2)⁢ⅆ⁡t=(-1)p+1⁢2ⅈ⁢π⁢cen⁡(0,h2)⁢cem⁡(0,h2)h⁢Dc0⁡(n,m,0).