The sum  of the coefficient of all odd degree terms in the expansion  of  x+x3−15+x−x3−15,x>1

We know that (x+a)5+(x-a)5=2C0   5x5+C2   5x3a2+C4   5xa4∴x+x3-15+x-x3-15=2C0   5x5+C2   5x3x3-1+C4   5xx3-12=2C0   5x5+C2   5x6-x3+C4   5xx6-2x3+1Thus, the sum of coefficient of all odd degree terms =2C0   5-C2   5+C4   5+C4   5=2[1-10+5+5]=2