Help! Trig Questions from 'Understanding Maths' (1 Viewer)

[lachy95]

So I'm pretty sure I've just bought a shit textbook, but can anyone explain the following questions (unless they are, as suspected, incorrect)? Thanks - I'd really appreciate it.

 

[Timske]

<a href="http://www.codecogs.com/eqnedit.php?latex=A@plus;B@plus;C=180 , B@plus;C=180-A \\ 2sin(B@plus;C)sinA = 2sin(180-A)sinA\\ 2sin(180-A)sinA=(2sin180cosA - 2cos180sinA)sinA \\ (-2cos180sinA)sinA = 2sin^2A \\2sin^2A = 1-(1-2sin^2A)= 1-cos2A = RHS" target="_blank"><img src="http://latex.codecogs.com/gif.latex?A+B+C=180 , B+C=180-A \\ 2sin(B+C)sinA = 2sin(180-A)sinA\\ 2sin(180-A)sinA=(2sin180cosA - 2cos180sinA)sinA \\ (-2cos180sinA)sinA = 2sin^2A \\2sin^2A = 1-(1-2sin^2A)= 1-cos2A = RHS" title="A+B+C=180 , B+C=180-A \\ 2sin(B+C)sinA = 2sin(180-A)sinA\\ 2sin(180-A)sinA=(2sin180cosA - 2cos180sinA)sinA \\ (-2cos180sinA)sinA = 2sin^2A \\2sin^2A = 1-(1-2sin^2A)= 1-cos2A = RHS" /></a>

 

[Sy123]

1)



2)



These really are great questions though heh.

Also the decimals are approximates to

 

[lachy95]

Thanks so much. Yeah missing out on the 1st question was stupid. But that 2nd question was really smart. Got to remember to reduce everything to tan if all else fails. What school do you go to?

 

[lachy95]

Also how do you actually embed the working out in LATEX instead of a picture?

 

[Sanjeet]

Also how do you actually embed the working out in LATEX instead of a picture?

type [ tex] (without the space obviously) and end with [/tex]

 

[Sy123]

You can use the tags {tex} *Insert Latex here* {/tex}. Except replace {} with []

There is a good beginners guide here: http://community.boredofstudies.org/showthread.php?t=234261

Or, if you want to first try out the latex by pressing buttons and stuff: http://www.codecogs.com/latex/eqneditor.php

For the second link you can just copy and paste the code into the {tex} and {/tex}tags

 

[gr_111]

For the second link you can just copy and paste the code into the {tex} and {/tex}tags

No, you just paste the code, without the tex tags, example:

<a href="http://www.codecogs.com/eqnedit.php?latex=y=x^2" target="_blank"><img src="http://latex.codecogs.com/gif.latex?y=x^2" title="y=x^2" /></a>

If i paste the code within the tex tags it looks like this:

 

[D94]

No, you just paste the code, without the tex tags, example:



If i paste the code within the tex tags it looks like this:

[/URL][/tex]

There are two different types. One is an image, ie. what you are showing, which isn't the best way especially when you want to edit it, IMO. The other way is the LaTeX code itself, when you have to place it in the tex tags. It might turn into an image, but when editing, it is LaTeX code.

Either way yields the same result.