plz solve this maths question
I will be thankful to u if u solve it
Answers
Solution:-
first hemisphere length=π×0.5=0.5πcm
second hemisphere=π×1=πcm
third hemisphere length=π×1.5=1.5πcm
fourth hemisphere length=π×2=2πcm
here we are seeing that AP is fromed of common difference 0.5π
length of.spiral=sum of 15terms of this AP
length of spiral=15/2(2×0.5π+14×0.5π)cm
=15×4π=60πcm
{sorry for mistake}
Solution :-
Let L₁, L₂, L₃, L₄, ........, L₁₃ be the lengths of semicircles of radii 0.5 cm, 1 cm, 2 cm .... and 13/2 cm respectively.
Then, we have
L₁ = π × 0.5 = π/2 cm,
L₂ = π × 1 = 2(π/2) cm,
L₃ = π × 1.5 = 3(π/2) cm,
L₄ = π × 2 = 4(π/2) cm,
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L₁₃ = π × 13/2 = 13(π/2) cm,
Therefore,
Total length of the spiral
= L₁ + L₂ + L₃ + L₄ + ....., + L₁₃
= [π/2 + 2(π/2) + 3(π/2) + 4(π/2) + ......., + 13(π/2)] cm
= π/2(1 + 2 + 3 + 4 + ........ + 13) cm
= π/2 × 13/2 × (1 + 13) cm
= (1/2 × 22/7 × 13/2 × 14) cm
= 143 cm.
Hence, the required length of the spiral is 143 cm.
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