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Is a line ax+by+c=0 tangent to a circle?

Get a line a form y=-ax/b-c/b, then substitute into a cirle equation (x-p)^2 +(y-s)^2=r^2. Get a quadratic and find whether a discriminant is equal to zero. If it is then the line is tangent to a circle. Oth...
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Answered by Jakub O. • Maths tutor
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How to structure an A-level History essay?

The important part to any History A-Level is the structure, as it not only shows the examiner your understanding of the question but also your level of knowledge. As an effectively structured argument can ma...
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Answered by Imogen H. • History tutor
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How does the Meselson and Stahl Experiment provide evidence for the semi conservative theory of DNA replication?

Before we start on the specifics of the experiment itself we need to understand how DNA replication occurs on a molecular level . DNA is made up of four different bases; A, C, G and T. Each base is attached ...
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Answered by Julia D. • Biology tutor
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How should I structure and plan a Section B question? (Edexcel)

With the Section B questions you will be asked to engage with a set of sources that are related to a historical debate relevant to your course. Before jumping straight into answering the question though you'...
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Answered by Charlie M. • History tutor
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Why do you use the subjunctive after 'quiero que'?

It should be said that it is not always trigged by that construction, since the subjunctive only follows this clause if there is a change in subject (i.e. quiero que tu hagas/usted haga/él haga/ella haga/nos...
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Answered by Zac L. • Spanish tutor
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