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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 per...

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.recal...

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 = -log₁₀[H+] So, we need to work out the concentration of H+ ions in 0.375 mol dm^-3 of nitrous acid, HNO

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) = x². As you will have learnt, you will need to use the chain rule f...

Answered by Lloyd K. • Maths tutor

4585 Views

What is the subjunctive and how do I use it?

The subjunctive is not a tense but a mood. Unlike the indicative, which is used to convey certainty, the subjunctive conveys doubt, desire or possibility, generally speaking. It has three forms in Spanish...

Answered by George H. • Spanish tutor

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