Calculus et Moi

Thursday, May 21, 2009

♥ The RRRR Method

puRRRR....Method for Calculus

This is my first methodology post for calculus,however wrong i might be afterall this is the method that i've applied thru out my practice for the Arre (R) Method. Since its my way,i will call it the AR.method aka Aiba Roslyn Method.

The R method exist with the objective in simplification of a sin X + b cos X ,where it can be simplify as R sin (w + z) and R cos ( w + z)

For example : A sin x + B cos X can be written as R sin (w + z) ,to open R sin ( w + z ) you will have to look at the Trigonometric identities Addition Formulas :

Commonly used Trigonometric identities Addition Formulas :

sin(X + Y) = sinX cosY + cosX sinY

cos(X - Y) = cosX cosY + sinX sinY

Therefore R sin ( w + z )

= Sin Cos + Cos Sin

PS: Eliminate the Alphabets infront of Sin and Cos if it confuse you better still you may skip this step.

Hereafter you will have to equate your coefficient :

R sin = The number of Cosine
R Cos = Vice Versa

For example if Sin = 7 , Cos = 10

It would be :

R sin = 10

R cos = 7

Ps: Forget about understanding WHY because it applies for all when doing the R method.

Then,square root both your cosine and sine as though you're applying pytheogras theorem.

It would be 10^2 + 7^2 = √149 = 12.2

Then look for Tan ^ -1 (tangent inverse) = Sin / Cos = Tan ^-1 ( 10 / 7) = 55 .

Viola . Then you have completed the R method if you have to define R sin ( w + z )