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The Volume of a tin of radius r cm is given by V=pi*(40r-r^2-r^3). Find the positive value of r for which dV/dr=0 and find the value of V for this r.

Firstly differentiate the function V with respect to x (dV/dx)=pi*(40-2r-3r^2). Set dV/dr =0 and solve to find r. Divide both sides by pi and divide both side by -1 so that the r^2 term is positive (I person...
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Answered by Chorley K. • Maths tutor
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how do i sketch the graph of y=ln(|x|) ?

To sketch any modulus function, we begin with the sketch of the function itself, y=ln(x). Notice that the question asks for the graph of y=ln(|x|) and not y=|ln(x)|, this is an important distinction.recall t...
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Answered by Dáire O. • Maths tutor
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Nitrous acid, HNO2, is a weak Bronsted-Lowry acid with a Ka value of 4.43x10-4 mol dm-3. Calculate the pH of 0.375 mol dm-3 of HNO2.

We know how to calculate pH from H+ concentration with the equation : pH = -log 10 [H+] So, we need to work out the concentration of H+ ions in 0.375 mol dm -3 of nitrous acid, HNO 2 . We're given the Ka val...
Answered by • Chemistry tutor
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How do I differentiate: (3x + 7)^2?

We can see that (3x + 7) 2 is a 'composite function'. We can rewrite this as g(f(x)), where f(x) = 3x + 7 and g(x) = x 2 . As you will have learnt, you will need to use the chain rule for this type of differ...
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Answered by Lloyd K. • Maths tutor
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What are the functions and processes of Parliament in holding the Executive to account?

The role of Parliament is split between the House of Commons and the House of Lords, and they both have different but compatible roles in holding the government to account over policy, actions and legislatio...
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