WSKT 212 PAC

Skets die kromme van
y = x −
2
2
9
2
( )
rsinθ = 2 rcosθ − 9 uit/ from x = rcos θ en/ and y = rsinθ
2 2
∴rsinθ − 2r cos θ + 9 = 0
2 2
∴− 2r cos θ + rsinθ
+ 9 = 0
∴− cos ⋅ r + sin ⋅ r + =
2 2
2 θ θ 9 0
− b ±
∴ r =
2
b − 4ac
2a
− sinθ ±
=
2 2
sin θ − 4 −2cos
θ
2 2
9
2 ( − cos θ )
− sin ± sin + cos
∴ r =
−4cos
θ
( )( )
θ
2
θ
2
72
2
θ
2 2
− sinθ ± sin θ + 72cos
θ
r =
met
2
−4cos
θ
behulp van GSP en vergelyk dit met
die grafiek wat u in 4.3 hierbo geteken
het.
Beskou die volgende grafiek wat toon
hoe die konsentrasie van ‘n
soutoplossing met verloop van tyd
verander:
Vraag 5/ Question 5
34
Sketch the curve of
2 2
− sinθ ± sin θ + 72cos
θ
r =
using
2
−4cos
θ
GSP and compare it to the graph which
you produced in 4.3 above.
Consider the following graph which
shows how the concentration of a salt
solution changes with the passing of
time: