SOLUTION: Give an example of irrational numbers a and b such the indicated expression is (1) rational and (2) irrational. 1) a + b 2) a - b 3) (a)(b) 4. (a/b)

Algebra ->  Real-numbers -> SOLUTION: Give an example of irrational numbers a and b such the indicated expression is (1) rational and (2) irrational. 1) a + b 2) a - b 3) (a)(b) 4. (a/b)       Log On


   



Question 1197044: Give an example of irrational numbers a and b such the indicated expression is (1) rational and (2) irrational.
1) a + b
2) a - b
3) (a)(b)
4. (a/b)

Answer by ikleyn(52748) About Me  (Show Source):
You can put this solution on YOUR website!
.

(1)  a = sqrt%282%29,  b = 1-sqrt%282%29.   a and b are irrational, but a+b = 1 is rational.


     a = 2%2Asqrt%282%29,  b = sqrt%282%29.   a and b are irrational, and a+b = 3%2Asqrt%282%29  is irrational.




(2)  a = sqrt%282%29,  b = sqrt%282%29-1.   a and b are irrational, but a-b = 1 is rational.


     a = 2%2Asqrt%282%29,  b = sqrt%282%29.  a and b are irrational, and a-b = sqrt%282%29  is irrational.




(3)  a = sqrt%282%29,  b = sqrt%282%29.    a and b are irrational, but a*b = 2 is rational.


     a = sqrt%282%29,  b = sqrt%283%29.    a and b are irrational, and a*b = sqrt%286%29 is irrational.




(4)  a = sqrt%282%29,  b = sqrt%282%29.   a and b are irrational, but a/b = 1 is rational.


     a = sqrt%286%29,  b = sqrt%283%29.   a and b are irrational, and a/b = sqrt%282%29 is irrational.

Solved.