C(15,2n+2)=C(15,n+1)
15-(2n+2)=n+1,n=4
(x-1/x)^n=(x-1/x)^4=(x^2-2+1/x^2)^2=(x^2+1/x^2)^2-4(x^2+1/x^2)+4=x^4+1/x^4-4(x^2+1/x^2)+6
常数项的值为6
C(15,2n+2)=C(15,n+1)
15-(2n+2)=n+1,n=4
(x-1/x)^n=(x-1/x)^4=(x^2-2+1/x^2)^2=(x^2+1/x^2)^2-4(x^2+1/x^2)+4=x^4+1/x^4-4(x^2+1/x^2)+6
常数项的值为6