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How do vaccinations work? Why don't they cause disease?

A vaccine is a weakened form of the disease causing bacteria injected in to the patient. The person then develops immunity to that bacteria and so when they are infected with the bacteria, they are able to q...
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Answered by Acrisa K. • Biology tutor
3275 Views

Why can metals conduct electricity?

The outer shell of electrons in metals are delocalised, meaning they are able to travel freely around the metal. The negative electrons hold the positively charged metal ions together. The pool of delocalise...
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Answered by Acrisa K. • Chemistry tutor
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Prove that one interior angle of a a regular octagon = 135 degrees

Regular octagon has 6 triangles within it. Total of interior angles in a triangle = 180 degrees So the total of interior angles within a regular octagon would = 180 x 6 (=1080). All angles in a regular octag...
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Answered by Acrisa K. • Maths tutor
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Given the parametric equations x = t^2 and y = 2t -1 find dy/dx

The first step is to find dx/dt and dy/dt, this is done using standard differentiation rules giving the resultsdx/dt = 2t dy/dt = 2 The second step is to eliminate dt. This can be done by the multiplication ...
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Answered by Matthew H. • Maths tutor
10107 Views

David travels from home to work at 30 mph. At the end of the day, he travels from work back home via the same route at 40 mph. What is his average speed while travelling? (Give your answer as a simplified fraction) (None-Calculator)

First set the distance between home and work as the value x miles.The time takento get from home to work is the value y hours.The time takento get from work to home is the value z hours.Then (as timeis equal...
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Answered by David F. • Maths tutor
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