Manipal MET2015MathematicsFunctions
The number of solutions of the equation 9 x^2-18|x|+5=0 belonging to the domain of definition of _e (x+1)(x+2) , is
Options
- A1
- B2
- C3
- D4
Correct answer
C. 3
Step-by-step solution
We have, 9 x^2-18|x|+5=0 array lr & 9|x|^2-18|x|+5=0 & (3|x|-1)(3|x|-5)=0 & |x|= 1 3 or |x|= 5 3 & x= 1 3 or x= 5 3 array Now, _ (x+1)(x+2) is defined, if (x+1)(x+2) 0 x -2 or x -1 Clearly, x=- 5 3 does not satisfy this condition. But all other values of x satisfy the above conditions. Hence, the number of solutions lying in the domain of definition of the given function is 3 .