plot curves in matlab

Hi. How can i plot below equation(qa vs w)?

thank you

(9*w^4*cos(qa))/28000000 - (33*w^2*cos(qa))/32000 - (105*cos(qa))/64 + (603*w^2)/2560000 - (4891*w^4)/4480000000 + (93*w^6)/560000000000 + 105/64=0

Answer 1

[John D'Errico]

fun = @(w,qa) (9*w.^4.*cos(qa))/28000000 - (33*w.^2.*cos(qa))/32000 - (105*cos(qa))/64 + (603*w.^2)/2560000 - (4891*w.^4)/4480000000 + (93*w.^6)/560000000000 + 105/64;
fimplicit(fun)

You can tell fimplicit how far out to go of course.

fimplicit(fun,[-100 100 -100 100])

It does appear as if much is happening when you broaden the view.

[saman ahmadi]

thanks. from plotting sended equation must plot a curve like image attachmented.

[John D'Errico]

Sigh. It would have helped if you asked that question in the first place, instead of just asking how to plot qa as a function of w.

fun = @(qa,w) (9*w.^4.*cos(qa))/28000000 - (33*w.^2.*cos(qa))/32000 - (105*cos(qa))/64 + (603*w.^2)/2560000 - (4891*w.^4)/4480000000 + (93*w.^6)/560000000000 + 105/64;
fimplicit(fun,[-pi pi 0 100])

If you are looking for a specific result, then you need to tell people. That seems to come pretty close, though the scaling of the variables seems to be different from the plot you show. That is more a question of the specific function you gave us, which is surely different from that which generated your plot.

Answer 2

[Alan Stevens]

Somethig like this:

qafn = @(w) acos(( 4891*w.^4/4480000000 -93*w.^6/560000000000 -603*w.^2/2560000 -105/64 )...
    ./(9*w.^4/28000000 - 33*w.^2/32000 - 105/64 ));

w = -50:50;
qa = qafn(w);

plot(w,qa)

[saman ahmadi]

thanks. from plotting sended equation must plot a curve like image attachmented.

[Alan Stevens]

So change the plotting range from -pi to pi in steps of pi/100, say, i.e. replace

w = -50:50;

with

w = -pi:pi/100:pi;

[saman ahmadi]

tihs code plot(w,qa) but, i want to plot (qa,w), how can i do it?

[Alan Stevens]

Oops! I've inverted everything!

[Alan Stevens]

Looks like the implicit function is the way to go, though the w axis is scaled differently.

qawfn = @(qa,w) (9*w.^4.*cos(qa))/28000000 - (33*w.^2.*cos(qa))/32000 - (105*cos(qa))/64 ...
+ (603*w.^2)/2560000 - (4891*w.^4)/4480000000 + (93*w.^6)/560000000000 + 105/64;
fimplicit(qawfn,[-pi pi 0  90])

[saman ahmadi]

thank you very much

dear Alan Stevens