# Pure maths questions

What topic is this in pure maths and please can I have help with all of the questions
(edited 1 year ago)
Original post by Matheen1
What topic is this in pure maths and please can I have help with all of the questions

These are questions about modelling with exponential functions. They don't require any new knowledge of these functions, but do require you to understand how they are being used in context. For example, to do part (i), you can use the fact that the heat is switched off when the temperature reaches 100°.
Original post by Pangol
These are questions about modelling with exponential functions. They don't require any new knowledge of these functions, but do require you to understand how they are being used in context. For example, to do part (i), you can use the fact that the heat is switched off when the temperature reaches 100°.

Ok that makes more sense now thanks. Can i have help with (iii) now please?
Original post by Matheen1
Ok that makes more sense now thanks. Can i have help with (iii) now please?

Just before that part, they talk about the rate of decrease of the temperature of the water. What piece of mathematical notation can we use for this? You might want to think about it as the rate of change of the temperature, since a decrease is a change and that form of words might be more familiar.
Original post by Pangol
Just before that part, they talk about the rate of decrease of the temperature of the water. What piece of mathematical notation can we use for this? You might want to think about it as the rate of change of the temperature, since a decrease is a change and that form of words might be more familiar.

Ok all done, just need help with part (v) now
Original post by Matheen1
Ok all done, just need help with part (v) now

How would a and k be affected by the water not reaching 100° before it starts to cool?

You don't have to say too much, this is only for one mark.