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If-the-point-2-p-and-2-q-lie-on-the-graph-y-x-3-ax-2-bx-c-and-q-p-3-then-what-the-value-of-b-




Question Number 105345 by bemath last updated on 28/Jul/20
If the point ((√2) ,p) and (−(√2),q)  lie on the graph y=x^3 +ax^2 +bx+c  and q−p = 3 , then what the  value of b ?
$${If}\:{the}\:{point}\:\left(\sqrt{\mathrm{2}}\:,{p}\right)\:{and}\:\left(−\sqrt{\mathrm{2}},{q}\right) \\ $$$${lie}\:{on}\:{the}\:{graph}\:{y}={x}^{\mathrm{3}} +{ax}^{\mathrm{2}} +{bx}+{c} \\ $$$${and}\:{q}−{p}\:=\:\mathrm{3}\:,\:{then}\:{what}\:{the} \\ $$$${value}\:{of}\:{b}\:?\: \\ $$
Answered by ajfour last updated on 28/Jul/20
p=2(√2)+2a+b(√2)+c  q=−2(√2)+2a−b(√2)+c  subtracting  −3=2(√2)(b+2)   ⇒  b=−2−((3(√2))/4)   b = −[2+(3/4)((√2))] .
$${p}=\mathrm{2}\sqrt{\mathrm{2}}+\mathrm{2}{a}+{b}\sqrt{\mathrm{2}}+{c} \\ $$$${q}=−\mathrm{2}\sqrt{\mathrm{2}}+\mathrm{2}{a}−{b}\sqrt{\mathrm{2}}+{c} \\ $$$${subtracting} \\ $$$$−\mathrm{3}=\mathrm{2}\sqrt{\mathrm{2}}\left({b}+\mathrm{2}\right)\:\:\:\Rightarrow\:\:{b}=−\mathrm{2}−\frac{\mathrm{3}\sqrt{\mathrm{2}}}{\mathrm{4}} \\ $$$$\:{b}\:=\:−\left[\mathrm{2}+\frac{\mathrm{3}}{\mathrm{4}}\left(\sqrt{\mathrm{2}}\right)\right]\:. \\ $$
Commented by bemath last updated on 28/Jul/20
cooll...
$${cooll}… \\ $$

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