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What is the difference between 'ходить' and 'идти'?

The verb 'to go' is so much more complicated in Russian than in English, but once you know the rules you can easily work out which verb to use in any situation, just by applying logic. Both 'ходить' and 'идт...
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Answered by Helena K. • Russian tutor
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What is an alkene and how might one be identified?

Alkenes are a family of hydrocarbons (compounds made up of only hydrogen and carbon atoms) that all share the same chemical formula, similar chemical properties (due to same functional group) and trends in p...
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Answered by Natasha C. • Chemistry tutor
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White paint costs £2.80 per litre. Blue paint costs £3.50 per litre. White paint and blue paint are mixed in the ratio 3 : 2 Work out the cost of 18 litres of the mixture.

To work out how many litres of white and blue paint is needed, use the ratio 3:2. To find the specifc ratio for 18 litres, of paint: 2+3=5, 18/5=3.6 so (3:2) 3.6 becomes 10.8:7.2 (check 10.8+7.2=18). So to d...
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Answered by Aidan D. • Maths tutor
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Using the equation cos(a+b) = cos(a)cos(b) - sin(a)sin(b) or otherwise, show that cos(2x) = 2cos^2(x) - 1.

First let a = b = x such that: cos(a + b) = cos(a)cos(b) - sin(a)sin(b) becomes: cos(x + x) = cos(x)cos(x) - sin(x)sin(x) Leading to: cos(2x) = cos 2 (x) - sin 2 (x) Using the fact that sin 2 (y) + cos 2 (y)...
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Answered by Benjamin H. • Maths tutor
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Give the definition simple harmonic motion and write down the defining equation for such motion stating the meaning of any symbols involved.

Simple harmonic motion is defined as a form of periodic motion in which a point or body oscillates in such a way that the acceleration of the point or body is directly proportional to its displacement from t...
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Answered by Benjamin H. • Physics tutor
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