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If f(x)=7-4x, given that f(c)=9, find c

f(c) means let x=c. Remember that c is just an unknown number. The expression f(c)=9 means that when we put c through the function f(x)=7-4x, it gives the answer 9. Therefore we know 7-4c=9 is true. Now we h...
EF
Answered by Emma F. • Maths tutor
9629 Views

Find the tangent of the following curve, y=xe^x, at x=1 expressing it in the form y=mx+c?

Firstly, we calculate the y-value when x=1, namely y=e. Then we need to find the gradient of this curve at x=1, which can be determined by taking the derivative of y and then valuate it at x=1. So dy/dx=xe^x...
BS
Answered by Bruno S. • Maths tutor
18824 Views

The government has introduced an ad valorem tax on petrol. The likely effect is: A) Increase in sales of petrol B) Increase in carbon emissions from electric cars C) Increase in demand for bus travel D) Decrease in sale of electric cars

Four mark questions are a great way to pick up marks. There is a simple strategy to remember when answering these. Firstly, always write down your definition of the key word(s). Even if you do not know the c...
BP
Answered by Binal P. • Economics tutor
3726 Views

What is a possible approach to analysing unseen texts?

In your exams and your essays in general, when asked to analyse unseen texts, your goal is to show a sophisticated reading and response. This can be quite difficult if you're not sure what to look for, if a ...
LH
6059 Views

given y=(1+x)^2, find dy/dx

There are two ways in which this we can do this, The first is explanding the brackets to get 1+2x+x 2 and differentiating to get 2+2x. The second way is using the chain rule , let u=1+x such that y=u 2 and d...
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Answered by Sam G. • Maths tutor
9150 Views