  # Rapper

Members

3

## Posts posted by Rapper

1. ### Minimal Area of a Cone

A cylinder with radius r=0.75 m and height h = 1 m has to be covered by a cone. Find the minimal area for the cone.

Surface Area of Cone: pi*r^2 + pi*r*L

So, I figured out:

H= Height of the cone

(H-1)/0.75 = H/R

H=-4R/(-4R+3)

To calculate L, I used the Pythagoras & substituted H from above:

L = sqrt(R^2+H^2)

L = sqrt(R^2+(-4R/(-4R+3))

L = (sqrt(16R^4-24R^3+25R^2)/(4R-3)

I see I'm heading towards something really complicated...

Could you please help me find the right way to do it? I have just started doing this.

2. ### Series/Sequences of numbers

Oh, I made a mistake, sorry...
It's

a(n+2) = [a(n) + a(n+1)]/2

How can I calculate a(5)?

3. ### Series/Sequences of numbers

Give an explicit form each of the terms:

a(1) = 1

a(2) = 3

a(n+1) = [a(n) + a(n+1)]/2

I just started with this topic. How can I calculate what a(n) is?

Should I replace a(n) by 1 and a(n+1) by 3 and divide the result by 2? Would that give me de?

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