Sequences and Series
The sum of first 9 terms of the series 113+1+313+23+1+2+313+23+33+.....is
A ladder has rungs 25 cm apart, (see Figure). The rungs decrease uniformly in length from 45 cm at the bottom to 25 cm at the top. If the top and the bottom rungs are 221m apart, what is the length of the wood required for the rungs?
A G.P. consists of an even number of terms. If the sum of all the terms is 5 times the sum of terms occupying odd places, then find its common ratio.
Sum of the first p, q and r terms of an A.P are a, b and c, respectively.Prove that pa(q−r)+qb(r−p)+rc(p−q)=0