Result of an inequation, different from the algebraic process. - Printable Version +- HP Forums (https://www.hpmuseum.org/forum) +-- Forum: HP Calculators (and very old HP Computers) (/forum-3.html) +--- Forum: HP Prime (/forum-5.html) +--- Thread: Result of an inequation, different from the algebraic process. (/thread-21733.html) |
Result of an inequation, different from the algebraic process. - compsystems - 05-13-2024 02:18 AM Hello solve(((x-2)/(x+2))<2,x,'=') [ENTER] returns set[x<-6,x>-2] this is (-2,+∞) union (-∞, -6) but my calculations give me another domain. (-2,+∞) union (-6,+∞) Where am I going wrong? step by step solution. ((x-2)/(x+2))<2 (x+2)>0 [(x+2)>0]+-2 (x+2-2)>(0-2) (x+0)>-2 x>-2 (-2,+∞) ((x-2)/(x+2))<2 [((x-2)/(x+2))<2]*(x+2) [((x-2)/(x+2))*(x+2)]<[2*(x+2)] (x-2)<(2*x+4) [(x-2)<(2*x+4)]+-2*x [(x-2*x-2)<(2*x-2*x+4)] (-x-2)<(4) (-x-2+2)<(4+2) (-x)<(6) [-x<6]*-1 [-1*-x<6*-1] (x)>(-6) (-6,+∞) Edit. a second case must be considered when the denominator is negative. RE: Result of an inequation, different from the algebraic process. - Jan 11 - 05-13-2024 05:26 AM Hi, Hp Prime solves this inequality well. I solved the inequality on paper, manually, and got the same answer as Prime. RE: Result of an inequation, different from the algebraic process. - parisse - 05-13-2024 06:11 AM Move 2 to the left member, rewrite as a fraction, then replace / by * (this will not change sign),and find the sign of a polynomial of degree 2. |