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Solve x^2 + x=12 by factorising

Start off with:x 2 +x=12Subtract 12 from both sides:x 2 +x-12=0Factorise:(x-3)(x+4)=0Solution is therefore:x=3 or x=-4
DB
Answered by Duwan B. • Maths tutor
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Why does ionisation energy increase across a period?

As you go across the period, the nuclear charge (or number of protons increase) but the shielding (or the number of shells) stays the same as all of the elements are on the same period. This causes the nucle...
AP
Answered by Anjali P. • Chemistry tutor
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Integrate ln(x) with respect to x.

Here we can use integration by parts. Notice that ln(x) can be written as ln(x) 1, so we can integrate 1 and differentiate ln(x). Then using the formula int(u v') dx = uv - int(u' v) dx, we find that the int...
TW
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If y=(a^(Sinx)) where a and k are given constants, find dy/dx in terms of a and x

Here we have to differentiate a constant raised to the power of a variable. To make it easier, let u=sinx and so our function can now be treated as y=a^u. Remembering that A = e^(LnA), a^u = e^(Ln(a^u)). Usi...
MD
Answered by Maninder D. • Maths tutor
3662 Views

When vaporised, isotopes of an element can be separated in a mass spectrometer. Name the three processes that occur in a mass spectrometer before the vaporised isotopes can be detected. State how each process is achieved. (6 marks)

Once the sample is vaporised, high energy electrons are fired at the sample which knocks off a loosely held electron. (1) This step is known as election impact ionisation. (2) Due to the presence of a charge...
MF
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