AP EAMCET202123 Aug 2021Evening ShiftMathematicsFunctionsActual
The range of the function f(x)=- 5-6 x-x^2 is
Options
- A[-2,2]
- B[- 14 , 0]
- C[2, ]
- D[-2,0]
Correct answer
B. [- 14 , 0]
Step-by-step solution
f(x)=- 5-6 x-x^2 Let f(x)=y aligned & y=- - (x^2+6 x-5 ) & -y= - (x^2+6 x+9-9-5 ) & -y= - (x+3)^2-14 aligned On squaring both sides, y^2=14-(x+3)^2 (x+3)^2=14-y^2 x= 14-y^2 -3 which is defined only when y [- 14 , 14 But f(x) will give only negative values. Hence, range of f(x)=[- 14 , 0]