Select and write the correct answer from the given alternatives in each of the following sub-questions :
`int_(4)^(9) (1)/(sqrt(x))dx=.......`

Options

A. 1
B. -2
C. 2
D. -1

Answer

C

Explanation

Let `I=underset(4)overset(9)int (x)^(-1//2)dx`
`=[(x^(1//2))/(1//2)]_(4)^(9)`
`=(2x^(1//2))_(4)^(9)`
`=2(sqrt(9)-sqrt(4))=2(3-2)=2`
Hence, correct answer from the given alternatives is (c).