if the (p)th term of an ap is (q) and the (q)th term is (p) then its (p+q)th term is

Answer: 0

Step-by-step solution

Step 1: State formula and write given equations

Let aa be the first term and dd be the common difference of the AP. Using the formula for the nthn^{\text{th}} term, an=a+(n−1)da_n = a + (n-1)d, we formulate two linear equations corresponding to the pthp^{\text{th}} and qthq^{\text{th}} terms.

Step 2: Solve for common difference d

Subtract equation (2) from equation (1) to eliminate the first term aa. This gives (p−q)d=−(p−q)(p-q)d = -(p-q). Since p≠qp \neq q, dividing both sides by (p−q)(p-q) yields d=−1d = -1.

Step 3: Find the first term a

Substitute d=−1d = -1 into equation (1). Solving for aa gives a=p+q−1a = p + q - 1.

Step 4: Calculate the (p + q)-th term

Now we compute the (p+q)th(p+q)^{\text{th}} term using ap+q=a+(p+q−1)da_{p+q} = a + (p+q-1)d. Substituting a=p+q−1a = p+q-1 and d=−1d = -1, the terms cancel out to yield 00.

Solve your own maths question free →