I'm trying to solve these as opposed to using the matrix method (which I don't fully understand yet) but can't see where I go wrong. e2 should be 1.8 but I'm getting 1.61. Could the difference be due to not using enough decimal places or something I'm not doing right?
First issue is that it is hard to read the image. So it is difficult to check your arithmetic. Based on:
I got your answers of 1.38 and 1.61 (the latter really should be rounded to 1.62 since I am getting 1.617). My guess is a) either the starting equations are wrong, or b) the answer of 1.8 is wrong.
Somewhat beside the point but why are you adding (1)+(2)? This is unnecessary. Just take your (3) (which is equivalent to (1) and substitute it into (2).
Incidentally, the matrix method is exactly the same as working with the equations, only it it more compact (less notation).
Finally, if you want to be lazy but still be correct, you just need to add E:
becomes 3.65E-4
Ok you got the same answers which is good. I'm not quite sure why I added (1) and (2) but I can see that you don't need to now.
I'm following a course, the PDF is here with the equations on page 16 and the solution on page 19.
Would the "E" button just be labelled "E" or do you have to press shift and something else?
Thanks
It looks to me that the equations that both you and I have written down match each other and match what is on page 17 (which is equivalent to what is on 16). Take your solutions and plug them into the original equations. If they both work, then you got it right and they have a typo. If not then we're doing something silly.
I just meant when posting a message or writing down on paper. But yes you can do it on a calculator, and on mine (some obscure and now out-dated TI-85), I think you just hit EE button. (i.e. 3.65EE-4 does what you want).
See your calculator manual for details.