Considering only the principal values of inverse trigonometric functions, the number of positive real values of x satisfying -1(x)+ -1(2x)= 4 is :
- more than 2
- 2
- 0
- 1
Answer
(4) 1
Solution
sum = 4< 2 with x>0, we need x 2x<1; then
-1x+ -12x= -1 3x1-2x2= 4
3x1-2x2=1
2x2+3x-1=0
x= -3 174
x>0: only x= 17-34 0.28 (and 2x2 0.16<1 ✓)
∴ one positive value
Answer: (4)