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Re: HOT Competition 4 Sep/8PM: If x^4 > 50, then which of the following mu
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04 Sep 2020, 19:36
target is
must be true x^4>50
lets solve each option wise considering value of x
A. |x|>3 ; least value would be (3.01) ,3.5, 4 ,5 ... or in (-ve) x always true for our target value ; correct option
B. x>2.5 ; x can be 2.51 , 2.55, 3 so on so which does not give always yes to our target ; eliminate B
C. x<2.5 ; x can be 2.4 ,1 and (-3) , (-4) this does not give always yes to our target ; eliminate C
D. 1/|x|<0.4 this can be written as 1/lxl<2/5 ; so least value of x can be 2.55,2.8,,2.9 , 3... so on we do not get always yes to our target eliminate D
E. 1/|x|>0.4 ; this can be written as 1/lxl>2/5 ; ; value of x can be 2,1 can be eliminated
OPTION A is correct
If x^4>50, then which of the following must be true?
A. |x|>3
B. x>2.5
C. x<2.5
D. 1/|x|<0.4
E. 1/|x|>0.4