Nose Cone

How to make a nose cone for 2-liter bottle rocket?

Okay so were making a botte rocket for sceince.
were using a two liter bottle and then we like taped a papertowel cylinder thing onto it.
we have poster board and we cut out fins but we dont know how to do the nose cone.
we want the point to be like super pointy.
but how do we do it?
PLEASE HELPP.

If your cone has height h and radius r, lateral surface can be made of paper or another flat material in shape of a sector of a circle with radius s
s = sqrt(h^2 + r^2)
s is also called slant height
and with central angle:
alpha = 2 pi r / s (rad)
or in degrees:
alpha = 360 r / s (°)
Links below include pictures

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