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To what extent does the impact of the First World War explain the outbreak of 2 revolutions in Russia in 1917?

The First World War displayed the ineffectiveness and under preparation of the Russian army as by 1917 there were c.4 million Russian soldiers dead and c.3 million wounded; this caused resentment towards a T...
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Answered by Ellie P. • History tutor
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Derive the following with respect to x1: y=(x1*x2)/(x1+x2).

y is a function of x 1 and x 2 . We are asked to derive y with respect to x 1 , meaning that x 2 remains constant. Note that y ' is the derivative of y. Both the numerator and denominator of the fraction con...
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Answered by Thaleia K. • Maths tutor
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Compare the structures of Diamond and Graphite, making references to the bonding, the shape of the structures, and location of the electrons within the structures. Account for the fact that graphite conducts electricity and diamond does not.

In diamond, each carbon atom forms 4 strong covalent sigma bonds with other carbons, resulting in a tetrahedral 3D arrangement of atoms where all the electrons are fixed in place or localised. In graphite, e...
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Answered by Ollie W. • Chemistry tutor
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A block of mass (m) is placed on a rough slope inclined at an angle (a) to the horizontal, find an expression in terms of (a) for the smallest coefficient of friction (x), such that the block does not fall down the slope.

The first thing to do as with any mechanics question is draw a force diagram with the weight (mg), the friction (F) and the normal reaction (R). As we are finding the smallest coefficient of friction possibl...
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Answered by Ollie W. • Physics tutor
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By using the substitution x = tan(u), find the integral of [1 / (x^2+1) dx] between the limits 1 and 0

First we need to change the limits, and by plugging in 1 and 0 to our substitution we find that the limits for u are arctan(1) and arctan(0) (or pi/4 and 0). Then we need to substitute for dx, and by differe...
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Answered by Ollie W. • Maths tutor
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