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How do I solve equations with unknowns in the denominators?

Suppose you have an equation: (2x+3)/(x-4) - (2x-8)/(2x+1) = 1 and you want to solve for x. Remember that you can only add fractions if they share a common denominator. Also that you can multiply the numerat...
SG
Answered by Seb G. Maths tutor
25319 Views

How do I evaluate composite functions?

Suppose you have 2 functions: f(x) = 3x 2 , g(x) = log 3 (x). These are arbitrary, any functions would work. Evaluate f(g(x)): let y = log 3 (x) ( = g(x) ), then f(g(x)) = f(y) = 3y 2 = 3[log 3 (x)] 2 . The ...
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Answered by Seb G. Maths tutor
4917 Views

How do I differentiate implicitly?

The most important thing to remember when differentiating implicitly is that y is a function of x. Rewriting y as y(x) often makes it much clearer. For example, evaluate d/dx (y 2 ): using the aforementioned...
SG
Answered by Seb G. Maths tutor
5192 Views

A cup of coffee is cooling down in a room following the equation x = 15 + 70e^(-t/40). Find the rate at which the temperature is decreasing when the coffee cools to 60°C.

First, we need to find the value of t when x = 6p°C. We are told that after t minutes the temperature, x, will be 60°C; so we can insert 60 into the equation for x: 60 = 15 + 70e^(-t/40) Secondly, we can rea...
NA
Answered by Nathan A. Maths tutor
12435 Views

How do you revise for an English Literature exam?

Ah yes, the question which haunted my years of study, particularly during GCSE and A Levels. At this stage, many exams are ‘open book’ - that is, you can take either a blank or highlighted copy of the text i...
SP
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