volumes of revolution

[steady storm]

help pls

[true plover]

To convert to Cartesian you get x=acos²θ and y=bsinθ/cosθ so y² = b²sin²θ/cos²θ = b²asin²θ/acos²θ = b²asin²θ/x = b²(a-acos²θ)/x = b²(a-x)/x

So y² = b²(a-x)/x

In Cartesian form

So y = ±b√[(a-x)/x]

Then sub in θ=π/6 and θ=π/3 to get corresponding values of x and you know in each case the distance between each value of y

I think

[steady storm]

i’ll try that now thanks!