Question

Explain why each of the following integrals is improper. (a) 4 x x − 3 dx 3 Since the integral has an infinite interval of integration, it is a Type 1 improper integral. Since the integral has an infinite discontinuity, it is a Type 2 improper integral. The integral is a proper integral. (b) [infinity] 1 1 + x3 dx 0 Since the integral has an infinite interval of integration, it is a Type 1 improper integral. Since the integral has an infinite discontinuity, it is a Type 2 improper integral. The integral is a proper integral. (c) [infinity] x2e−x2 dx −[infinity] Since the integral has an infinite interval of integration, it is a Type 1 improper integral. Since the integral has an infinite discontinuity, it is a Type 2 improper integral. The integral is a proper integral. (d) π/4 cot(x) dx 0 Since the integral has an infinite interval of integration, it is a Type 1 improper integral. Since the integral has an infinite discontinuity, it is a Type 2 improper integral. The integral is a proper integral.

Answer 1

Answer:

a

   Since the integral has an infinite discontinuity, it is a Type 2 improper integral

b

   Since the integral has an infinite interval of integration, it is a Type 1 improper integral

c

  Since the integral has an infinite interval of integration, it is a Type 1 improper integral

d

     Since the integral has an infinite discontinuity, it is a Type 2 improper integral

Step-by-step explanation:

Considering  a

          $\int\limits^4_3 {\frac{x}{x- 3} } \, dx$

Looking at this we that at x = 3   this  integral will be  infinitely discontinuous

Considering  b    

        $\int\limits^{\infty}_0 {\frac{1}{1 + x^3} } \, dx$

Looking at this integral we see that the interval is between $0 \ and \ \infty$ which means that the integral has an infinite interval of integration , hence it is  a Type 1 improper integral

Considering  c

       $\int\limits^{\infty}_{- \infty} {x^2 e^{-x^2}} \, dx$

Looking at this integral we see that the interval is between $-\infty \ and \ \infty$ which means that the integral has an infinite interval of integration , hence it is  a Type 1 improper integral

Considering  d

        $\int\limits^{\frac{\pi}{4} }_0 {cot (x)} \, dx$

Looking at the integral  we see that  at  x =  0  cot (0) will be infinity  hence the  integral has an infinite discontinuity , so  it is a  Type 2 improper integral