[Cleoleo]

for this q, to find the value of t, how do you know you need to sub 4 into 8cost rather than 2root 3 in the y equation to get t?

Thanks

[ian.slater]

(Original post by Cleoleo)
for this q, to find the value of t, how do you know you need to sub 4 into 8cost rather than 2root 3 in the y equation to get t?

Thanks

You need to find a value of t that gives the right value for both x and y. So check both.

[aznkid66]

Alternatively, you can look at the graph.

y=4sin(2t) intersects y=2sqrt(3) at two points when 0≤t≤pi/2.
The first (smaller x) is the one for point P, while the second (larger x) is the one for the other point.

x=8cos(t), 0≤t≤pi/2
As t goes from 0 to pi/2, cos(t) goes from 1 to 0. Thus the smaller x has the larger t, so pick the larger value out of the two for t.