x^2+(y+2)^2<16 (x+1)^2/64+(y+2)^2>1
D Deleted member 4993 Guest May 4, 2010 #2 vlh said: x^2+(y+2)^2<16 (x+1)^2/64+(y+2)^2>1 Click to expand... Please show us your work, indicating exactly where you are stuck - so that we may know where to begin to help you.
vlh said: x^2+(y+2)^2<16 (x+1)^2/64+(y+2)^2>1 Click to expand... Please show us your work, indicating exactly where you are stuck - so that we may know where to begin to help you.
B BigGlenntheHeavy Senior Member Joined Mar 8, 2009 Messages 1,577 May 5, 2010 #4 \(\displaystyle Here \ is \ the \ graphs \ of \ x^2+(y+2)^2 \ = \ 16 \ and \ \frac{(x+1)^2}{8^2}+\frac{(y+2)^2}{1^2} \ = \ 1.\) [attachment=0:3vwrv8uo]pqr.jpg[/attachment:3vwrv8uo] Attachments pqr.jpg 20 KB · Views: 283
\(\displaystyle Here \ is \ the \ graphs \ of \ x^2+(y+2)^2 \ = \ 16 \ and \ \frac{(x+1)^2}{8^2}+\frac{(y+2)^2}{1^2} \ = \ 1.\) [attachment=0:3vwrv8uo]pqr.jpg[/attachment:3vwrv8uo]
S soroban Elite Member Joined Jan 28, 2005 Messages 5,586 May 5, 2010 #5 Hello, vlh! Here's a start . . . \(\displaystyle \begin{array}{cccc}x^2+(y+2)^2 &<& 16 & [1] \\ \\[-3mm]\dfrac{(x+1)^2}{64}+(y+2)^2 &>& 1 & [2] \end{array}\) Click to expand... \(\displaystyle \begin{array}{ccccccc}\text{Multiply [2] by -1:} & -\dfrac{(x+1)^2}{64} - (y+2)^2) &<& -1 \\ \\ \text{Add [1]:} & x^2 + (y+2)^2 &<& 16 \\ \\ \text{And we have:} & x^2 - \dfrac{(x+1)^2}{64} & <& 15 \\ \\ \text{which simplifies: } & 63x^2 - 2x - 961 &<& 0 \end{array}\) \(\displaystyle \text{This is an up-opening parabola. }\;\text{It is negative between its x-intercepts.}\) \(\displaystyle \text{Quadratic Formula }\;x \;=\;\frac{2 \pm\sqrt{242176}}{126} \;\approx\;\begin{Bmatrix}3.922 \\ \text{-}3.890\end{Bmatrix}\) \(\displaystyle \text{Therefore: }\;-3.890 \;<\;x\;<\;3.922\) . . which seems to agree with BigGlenn's graph .
Hello, vlh! Here's a start . . . \(\displaystyle \begin{array}{cccc}x^2+(y+2)^2 &<& 16 & [1] \\ \\[-3mm]\dfrac{(x+1)^2}{64}+(y+2)^2 &>& 1 & [2] \end{array}\) Click to expand... \(\displaystyle \begin{array}{ccccccc}\text{Multiply [2] by -1:} & -\dfrac{(x+1)^2}{64} - (y+2)^2) &<& -1 \\ \\ \text{Add [1]:} & x^2 + (y+2)^2 &<& 16 \\ \\ \text{And we have:} & x^2 - \dfrac{(x+1)^2}{64} & <& 15 \\ \\ \text{which simplifies: } & 63x^2 - 2x - 961 &<& 0 \end{array}\) \(\displaystyle \text{This is an up-opening parabola. }\;\text{It is negative between its x-intercepts.}\) \(\displaystyle \text{Quadratic Formula }\;x \;=\;\frac{2 \pm\sqrt{242176}}{126} \;\approx\;\begin{Bmatrix}3.922 \\ \text{-}3.890\end{Bmatrix}\) \(\displaystyle \text{Therefore: }\;-3.890 \;<\;x\;<\;3.922\) . . which seems to agree with BigGlenn's graph .