Hi guys here is my question cos3x= sinx for the domain--- 0</ x </ Pi/2

any help would be appreciated

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- Oct 25th 2013, 11:43 PMGurp925Trig equation help!!
Hi guys here is my question cos3x= sinx for the domain--- 0</ x </ Pi/2

any help would be appreciated - Oct 26th 2013, 12:19 AMMINOANMANRe: Trig equation help!!
Transform the equation like this.... sin(90-3x)=sinx then the rest is easy.............

- Oct 26th 2013, 12:24 AMGurp925Re: Trig equation help!!
How did you get sin(90-3X) ?

- Oct 26th 2013, 01:23 AMProve ItRe: Trig equation help!!
- Oct 26th 2013, 07:08 AMMINOANMANRe: Trig equation help!!
I don't understand why some people complicate things to such extend that their advises become useless for the students.

as I said cos3x=sin(90-3x) this is a formula of basic trigonometry no doubt about that.

then the equation is transformed to sin(90-3x) =sinx

this yields two formulas of general solutions..

1. 90-3x =(360)κ +x

2. 90-3x = (360)k+(180-x)

where k is an arbitrary integer...that is to be chosen to fit your given interval.....

no need to expand and get a qubic equation...........................