how do i do this

[richbyers]

for my studies i am currently going through equations and so on....i know how to do the working of the following- what i dont know is how to do it on a calculator properly- i keep having to split the equation in half...so here it is

Ffi= (1/4.14x10power-15) X [(-13.6/3 squared) - (-13.6/2 squared)]

NOW- what i can do is get the correct answer...however not when putting the equation in full. i guess its because im typing the double brackets in wrong- and also the minuses are going wrong

what i ended up doing was the brackets part then answer X 1/4.14 x 1o power-15/....got the right answer but id still like to know how to do it fully

thanks

rich

[acey]

for my studies i am currently going through equations and so on....i know how to do the working of the following- what i dont know is how to do it on a calculator properly- i keep having to split the equation in half...so here it is

Ffi= 1/4.14x10power-15 X [(-13.6/3 squared) - (-13.6/2 squared)]

Depends what sort of calculator you've got. If it has a +/- key then use that for the negative terms in the brackets, otherwise make things easier for yourself by first simplifying it:

[(-13.6/3 squared) - (-13.6/2 squared)]

= [(-13.6/3 squared) + 13.6/2 squared)]

= [(13.6/2 squared) - (13.6/3 squared)]

= (13.6/4) - (13.6/9)

=17/9

If instead you mean (-13.6/3)^2 - (-13.6/2)^2 then it's the same as (13.6/3)^2 - (13.6/2)^2. Be careful when you apply "squared" on the calculator and make sure you're only squaring what you want to.

Your notation for the other factor is also ambiguous: you might mean

1/(4.14x10power-15) = (1/4.14) x 10^15

or

(1/4.14)x10power-15 = (1/4.14) x 10^(-15)

But it sounds like you know what you want for that term so no problem.

[richbyers]

thanks for the advice, ill take a better look at my calculator- as for the ambiguous way i set it out, i can understand how that would come about - i couldnt figure out how to type it properly as a forum message, so it probably looks worse than what ive got down on paper- ive added another set of brackets that might make it a bit clearer

rich