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2024 National Preliminary mathematics Topic 47 Free

Parametric equations, ellipses and hyperbolas

Cartesian equation from $x=2t+3$, $y=t^2+5$ · Sub-topic 1

PRELIMINARY CONTEST 2024

Contest 4

Tsito SHTS – 55 pts (Winner)

Methodist Girls’ SHS, Mamfe – 48 pts

Notre Dame Seminary SHS – 45 pts

Contest 5

Tema Methodist SHS – 54 pts (Winner)

Shama SHS – 37 pts

Bolgatanga SHS – 28 pts

Contest 6

Wallahs Academy – 32 pts (Winner)

O’Reilly SHS – 29 pts

Adanwomase SHS – 25 pts


ROUND 1

FIRST SET OF QUESTIONS

Find an equation in $x$ and $y$ in the form $y = f(x)$ from the given equation

QUESTION

1. $x=2t+3$ and $y=t^{2}+5$

SOLUTION

$x=2t+3$

$t=\frac{x-3}{2}$

$y=t^{2}+5$

$y=(\frac{x-3}{2})^{2}+5$


2. $x=3t-5$ and $y=t^{2}-6$

SOLUTION

$x=3t-5$

$t=\frac{x+5}{3}$

$y=t^{2}-6$

$y=(\frac{x+5}{3})^{2}-6$


3. $x=4t-1 and y=t^{2}+2$

SOLUTION

$x=4t-1$

$t=\frac{x+1}{4}$

$y=t^{2}+2$

$y=(\frac{x+1}{4})^{2}+2$


PRACTICE QUESTIONS


1. Find an equation in $x$ and $y$ in the form $y=f(x)$ from $x=2t+3$ and $y=t^2+5$.

ANSWER: $y=\dfrac{(x-3)^2}{4}+5$


SOLUTION

Isolate $t$ from the $x$ equation:

$x-3=2t$

$t=\dfrac{x-3}{2}$

Substitute into the $y$ equation:

$y=\left(\dfrac{x-3}{2}\right)^2+5$

$y=\dfrac{(x-3)^2}{4}+5$


2. Find an equation in $x$ and $y$ in the form $y=f(x)$ from $x=3t-5$ and $y=t^2-6$.

ANSWER: $y=\dfrac{(x+5)^2}{9}-6$


SOLUTION

Isolate $t$ from the $x$ equation:

$x+5=3t$

$t=\dfrac{x+5}{3}$

Substitute into the $y$ equation:

$y=\left(\dfrac{x+5}{3}\right)^2-6$

$y=\dfrac{(x+5)^2}{9}-6$


3. Find an equation in $x$ and $y$ in the form $y=f(x)$ from $x=4t-1$ and $y=t^2+2$.

ANSWER: $y=\dfrac{(x+1)^2}{16}+2$


SOLUTION

Isolate $t$ from the $x$ equation:

$x+1=4t$

$t=\dfrac{x+1}{4}$

Substitute into the $y$ equation:

$y=\left(\dfrac{x+1}{4}\right)^2+2$

$y=\dfrac{(x+1)^2}{16}+2$


4. Find an equation in $x$ and $y$ in the form $y=f(x)$ from $x=5t+2$ and $y=t^2-3$.

ANSWER: $y=\dfrac{(x-2)^2}{25}-3$


SOLUTION

Isolate $t$ from the $x$ equation:

$x-2=5t$

$t=\dfrac{x-2}{5}$

Substitute into the $y$ equation:

$y=\left(\dfrac{x-2}{5}\right)^2-3$

$y=\dfrac{(x-2)^2}{25}-3$


5. Find an equation in $x$ and $y$ in the form $y=f(x)$ from $x=2t-7$ and $y=t^2+4$.

ANSWER: $y=\dfrac{(x+7)^2}{4}+4$


SOLUTION

Isolate $t$ from the $x$ equation:

$x+7=2t$

$t=\dfrac{x+7}{2}$

Substitute into the $y$ equation:

$y=\left(\dfrac{x+7}{2}\right)^2+4$

$y=\dfrac{(x+7)^2}{4}+4$


6. Find an equation in $x$ and $y$ in the form $y=f(x)$ from $x=3t+1$ and $y=t^2+8$.

ANSWER: $y=\dfrac{(x-1)^2}{9}+8$


SOLUTION

Isolate $t$ from the $x$ equation:

$x-1=3t$

$t=\dfrac{x-1}{3}$

Substitute into the $y$ equation:

$y=\left(\dfrac{x-1}{3}\right)^2+8$

$y=\dfrac{(x-1)^2}{9}+8$