[Boards: 3 / a / aco / adv / an / asp / b / biz / c / cgl / ck / cm / co / d / diy / e / fa / fit / g / gd / gif / h / hc / his / hm / hr / i / ic / int / jp / k / lgbt / lit / m / mlp / mu / n / news / o / out / p / po / pol / qa / qst / r / r9k / s / s4s / sci / soc / sp / t / tg / toy / trash / trv / tv / u / v / vg / vp / vr / w / wg / wsg / wsr / x / y ] [Search | Home]
Sorry for a stupid question, just haven't...
Images are sometimes not shown due to bandwidth/network limitations. Refreshing the page usually helps.

You are currently reading a thread in /sci/ - Science & Math

File: new.png (9 KB, 667x184) Image search: [iqdb] [SauceNao] [Google]
9 KB, 667x184
Sorry for a stupid question, just haven't dealt with maths in quite a while, would be grateful if someone could explain this school grade math equation to me. Pic related.
>>
>>7795863
Did you ever learn how to do plane rotations?
>>
>>7795870
yea.. which was quite some time ago..
>>
>>7795863
Im thinking definite integral and playing around with sinhx and coshx maybe?
>>
anyone?
>>
replace y with (x+y)/sqrt(2) and y with (x-y)/sqrt(2)
use these new variables
>>
>>7795935
can you explain the reasoning? what is the full formula with cos and sin?
>>
>>7796006
x= xcos theta - y costheta
y = x sintheta + y cos(theta)

or something like that. Look up quadratic forms (matrices) and rotations of (x, y) column vectors.

The formula for what you have is z = Tranpose(v) tranpose(R) [1/a^2 0 0 -1/b^2] R v

where v is [x y] in column form and R is your rotation matrix and [1/a^2 0 0 -1/b^2] is an obvious 2x2 Matrix.