Find the sum of the first n terms of Tr = 2r + 2r - 1 (its the sum of an arithmetic and geometric series)
I got n2 - n/2 + 2n+1 - 2
But the textbook says n2 + 2n+1 - 2
Prove that 2n+2 + 32n+1 is divisible by 7 for all integers, n > 0
So far I have:
Let n = 1
23 + 33 = 8 + 27 = 35, which is divisible by 7
Assume true for n = k
2k+2 + 32k+1 = 7M
Consider n = k + 1
2k+3 + 32k+3
= 2k.23 + 32k + 33
= 2k.8 + 9k.27
= 2k.8 + 9.(3.9k)
= 2k.8 +...
A bowl is formed by rotating the part of the curve y = x^4 / 4 between x=0 and x=2 about the y axis.
Find the volume of the bowl.
From: 2002 Mathematics Exam (2 Unit)
Re: HSC 2013 3U Marathon Thread
Integration - Volume of Solids of Revolution
A hemispherical bowl of radius a units is filled with water to a depth of a/2 units. Find, by integration, the volume of the water.
The normals to the parabola x2 = 4Ay at the points P1 and P2 intersect at Q. If the chord P1P2 varies in such a way that it always passes through the point (0, –2A), show that Q lies on the parabola.
A rotating light L is situated at sea 180 metres from the nearest point P on a straight shoreline. The light rotates through one revolution every 10 seconds. Show that the rate at which a ray of light moves along the shore at a point 300 metres from P is (136) pi m/s.
So far I have:
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