According to Descartes' Rule of Signs, can the polynomial function have exactly 1 positive real zero, including any repeated zeros? Choose your answer based on the rule only.g(x)=x7−5x6−7x5−3x2+2x−2Choices:(A)yes(B)no
Q. According to Descartes' Rule of Signs, can the polynomial function have exactly 1 positive real zero, including any repeated zeros? Choose your answer based on the rule only.g(x)=x7−5x6−7x5−3x2+2x−2Choices:(A)yes(B)no
Count Sign Changes: Count the number of sign changes in the coefficients of g(x)=x7−5x6−7x5−3x2+2x−2. Coefficients: 1,−5,−7,0,0,−3,2,−2. Sign changes: 1 to −5 (no change), −5 to −7 (no change), −7 to 0 (no change), 0 to −3 (no change), −3 to 1,−5,−7,0,0,−3,2,−21 (change), 1,−5,−7,0,0,−3,2,−21 to 1,−5,−7,0,0,−3,2,−23 (change). Total sign changes: 1,−5,−7,0,0,−3,2,−21.
Descartes' Rule of Signs: According to Descartes' Rule of Signs, the number of positive real zeros is equal to the number of sign changes or less than that by an even number.So, g(x) can have 2 or 0 positive real zeros.
Number of Positive Zeros: Since g(x) can have 2 or 0 positive real zeros, it cannot have exactly 1 positive real zero.