Polar Coordinates and Conics, bad

[th3plan]

Were on the conic section. I need help how to choose the right interval to evaluate the arc lengh. x=5cost-cos5t and y=5sint-sin5t . I don't get how to choose the inverval to evaluate this, can someone pleasse tell me how. I just don't grasp this.

 

[Schrodinger's Dog]

Does this help?

= \int_{a}^{b} \sqrt { [x'(t)]^2 + [y'(t)]^2 }\, dt.

5 cos(t) - cos(5t) and 5 sin(t)- sin(5t) will no doubt fall within an area between x\pi \theta and x\pi\theta do you know how to work that out? Or how to work out appropriate ranges for cos and sin?

Personally I'd chose something like between 0 and \pi... or 0 and 2\pi

 

[HallsofIvy]

Were on the conic section. I need help how to choose the right interval to evaluate the arc lengh. x=5cost-cos5t and y=5sint-sin5t . I don't get how to choose the inverval to evaluate this, can someone pleasse tell me how. I just don't grasp this.

Those parametric equations do NOT give a conic section.

You can, however, cover the figure by letting t go from 0 to 2\pi

 

[th3plan]

how do i mathematically find the right interval to evaulate it ?

 

[Schrodinger's Dog]

how do i mathematically find the right interval to evaulate it ?

Which range will your shape fall in?

It's between the range of 0 and 360 degrees (or a full circle) right? In that case what is the range/interval in degrees to radians? Couldn't be 0 to 2\pi could it?

\text{radians}=\text{degrees}\times\frac{\pi\;\text{radians}}{180}

\text{degrees}=\text{radians}\times\frac{180}{\pi\;\text{radians}}