# plz can any one help me to plot this equation

#### nouredinne

i want to plot θ against β

Sin(θ-β)-2sin(2(θ-β))-sin(2θ)=0

0°<​θ<90°

0°<β<90°
(Speechless)

#### topsquark

Forum Staff
In order to plot this in a "traditional" sense you would have to solve for $$\displaystyle \beta$$ as a function of $$\displaystyle \theta$$. This is not going to be easy for this case, but it is possible. The better way would be to plot this as a "relation" rather than as a function. There are a number of online resources that you can find that will do this for you. Wolfram|Alpha is a good site but I don't remember off the cuff how to tell it to graph this.

-Dan

#### johng

Here's your graph; $\theta$ and $\beta$ are in radians. The red "curve" is your graph. You can see that $\beta$ is not a function of $\theta$ and $\theta$ is not a function of $\beta$. The given relation's graph for arbitrary theta and beta is shown outside the red square.

1 person

#### nouredinne

thank you johng, i have seen this result , but in ohter side some give this plot. i m not understund how obtain this graph

#### nouredinne

thank you topsquark, i want to obtain this graph

#### nouredinne

i have an other condition can help !!!

cos(θ-β)-2sin(2(θ-β))-cos(2θ)≥0

#### chiro

MHF Helper
Try solving for the derivative at a particular point and then step through it based on that.

You can solve plotting of relations that aren't functions in this manner.