Definite Integration Question 8

Question 8

  1. If I(m,n)=01tm(1+t)ndt, then the expression for I(m,n) in terms of I(m+1,n1) is

(2003, 1M)

(a) 2nm+1nm+1I(m+1,n1)

(b) nm+1I(m+1,n1)

(c) 2nm+1+nm+1I(m+1,n1)

(d) mm+1I(m+1,n1)

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Answer:

Correct Answer: 8. (a)

Solution:

  1. Here, I(m,n)=01tm(1+t)ndt reduce into I(m+1,n1) [we apply integration by parts taking (1+t)n as first and tm as second function]

$$ \begin{aligned} \therefore I(m, n) & =(1+t)^{n} \cdot \frac{t^{m+1}}{m+1}{ }{0}^{1}-\int{0}^{1} n(1+t)^{(n-1)} \cdot \frac{t^{m+1}}{m+1} d t \ & =\frac{2^{n}}{m+1}-\frac{n}{m+1} \int_{0}^{1}(1+t)^{(n-1)} \cdot t^{m+1} d t \ \therefore \quad I(m, n) & =\frac{2^{n}}{m+1}-\frac{n}{m+1} \cdot I(m+1, n-1) \end{aligned} $$



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