Question

Please answer the following by coding in R with comments ! Thank you!!!

Evaluation of a square root is achieved using the sqrt() function, but a warning will be issued when the argument is negative. Consider the following code which is designed to test whether a given value is positive before checking whether the square root of the value is less than 5.

testValue <-7

(testValue > 0) & (sqrt(testValue) < 5)

## [1] TRUE

testValue <--7

(testValue > 0) & (sqrt(testValue) < 5)

## Warning in sqrt(testValue): NaNs produced

## [1] FALSE

Modify the code so that it continues to give the correct answer but without the warning.

Answer 1

Here we require that if the first condition in predicate is evaluated to false, we shhould simply return false & not evaluate sqrt which would lead to warning. Thus, we want the conjunction operator to support short circuiting. In R, however logical operator '&' does not support circuiting but relational operator '&&' does, so we simply need to replace & with && in the given code.

testValue <-7

(testValue > 0) && (sqrt(testValue) < 5)

testValue <--7

(testValue > 0) && (sqrt(testValue) < 5)