(2n+1) (2n+3) (2n+5)......(4n-1) is equal to:
E = (2n+1) (2n+3) (2n+5)......(4n-1)
Multiply numerator and denominator by (2n+2) (2n+4) .....(4n) & also by (2n)!
Study 40% syllabus and score up to 100% marks in JEE