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Use the substitution u = 6 - x^2 to find the value of the integral of (x^3)/(sqrt(6-x^2)) between the limits of x = 1 and x = 2 (AQA core 3 maths

When integrating by substitution the first thing to do is change the limits of the integral by subbing them into the equation for u. This gives u = 5 as the lower limit and u = 2 for the upper limit. The nex...
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Answered by Christopher C. • Maths tutor
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Which food chain has the highest proportion of energy transfer. Grass -> cow -> human. Grass -> grasshopper -> rat -> snake. Rice -> human

Rice -> human. due to it having the fewest trofic levels (stages in the food chain) with each trofic level energy is lost through heat and movement as well as energy lost due to unabsorbtion in the digest...
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Answered by Ryan M. • Biology tutor
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How would you synthesise an carboxylic acid just from a primary haloalkane like bromoethane?

Nucleophilic substitution using NaOH to convert haloalkane to primary alcohol. This is a mechanism that you need to know for the exam. Then oxidise the alcohol by refluxing with acidified potassium dichromat...
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Answered by Ollie W. • Chemistry tutor
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Integration

Integration is a simple way of "quickly" adding. In cases where you have a curve under a graph for example a velocity-time graph, the area under the curve will give you the distance. If you know th...
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Answered by Neal A. • Maths tutor
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Mechanics 1: How do you calculate the magnitude of impulse exerted on a particle during a collision of two particles, given their masses and velocities.

Conservation of momentum is the key principle always used in problems of these type. Here, it asks for the impulse, which is a force measured in Newtons, and it is defined as the change in momentum. F=m(v-u)...
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Answered by Ina H. • Maths tutor
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