# logs ... easy ... right

Discussion in 'Mathematics' started by florapost, Mar 15, 2011.

1. ### florapost

oh lor - sisigmund the mad maths mistress (my favorite teacher ever) told me that one in 1967

I've just taught logs for the first time, found that the best way to deal with it was to get students to treat it like a formula - write down seperately a, x, and N, then look at the two ways of writing the relationship and see which one allows you to plug numbers into your calculator.

3. ### ResourceFinder

A good joke never goes out of fashion

4. ### ResourceFinder

Well I did discover one "issue"

Sam could use log3(n) = 8 to write 3^8 = n

And could work log3(81) out because, as he said ... 3^4=81

So

log3(n) = 1.5

Nope, no way, no idea
Eventually it transpired that he could not work out 3^1.5 and he was not sure what it meant so he thought it could not be the answer

5. ### Betamale

I asked a y12 on tuesday to share his answer to a question.
"I lost you when you got to" (pointing at the second line of my working
"How was x^2 - 2x = 0 become x(x-2)?"
Unless kids have a good reason which is supported by their teacher, IMO all A level entries must have A or higher at GCSE now.

6. ### rustybug

Could not agree more. I have an M1 class now who can take moments but haven't the skills to solve the two resulting equations simultaneously.

7. ### Betamale

Hi Paul
On the first point, no he had brain fade on surds graphing linear functions, any form of series or expansions and cannot even access the bottom end of trig. He is not alone in the class.
Fully agree on the second point and with a cracking work ethic and or maths maturity' some do ok. I am yet to see a true B grade ability student do very well.
On the algebrabit, yes you can get an A on last years Edexcel paper without doing algebra or any 'testing' GCSE number work.
I have a GCSE student who has been accepted onto A level maths who calls anything squared That little 2 thingy, believes 2^3 is 6 and doesnt know the formula for the area of a circle or triangle. He cannot add, subtract, multiply or divide fractions, cannot believe 2.5 and 5/2 are equal and cannot access anything beyond pythagorian triples when it comes to trig. He will get a B as will his other 3 friends of equal limited ability who already have been accepted