1
$\begingroup$

I am fairly new to Mathematica, so this may be a simplistic question, but I want to learn. I know how to use the Solve function to solve a single equation like this:

$$\cos[41.614-x]-1.2752|cos[1.607x]+7.1644\sin[1.607x]=0$$

and I know how to use Solve to solve a trigonometric equation like this:

equation=1-2Cos[x]-2Sin[x]+4Sin[2x]==0
Solve[equation,x]

However, when I try to solve my equation using Solve or NSolve Nothing comes up. I use following code

equation=Cos[41.614−x]−1.2752*Cos[1.607x]+7.1644*sin[1.607x]==0
Solve[equation,x]

What do I need to do to get Mathematica to give me a value of theta in degrees? I am sure there is a straightforward solution, but I just can't seem to find it. Thank you!

$\endgroup$

1 Answer 1

2
$\begingroup$

If you fix sin to Sin and help NSolve (not Solve) a little by giving range of x then it can do it

ClearAll[x]; 
equation = Cos[41.614 - x] - 1.2752*Cos[1.607*x] + 7.1644*Sin[1.607*x] == 0; 
NSolve[equation && -4*Pi < x < 4*Pi, x]

gives

{{x -> -11.5371}, {x -> -9.61635}, {x -> -7.76423}, {x -> -5.83644}, \
{x -> -3.81118}, {x -> -1.77431}, {x -> 0.180699}, {x -> 
   2.03885}, {x -> 3.93373}, {x -> 5.93711}, {x -> 7.98094}, {x -> 
   9.96783}, {x -> 11.8458}}

Solve can't solve this type of equation. Need to use numerical solver.

$\endgroup$
1
  • $\begingroup$ Thanks a lot. It works now. $\endgroup$
    – Ahlam
    Commented Apr 8, 2020 at 7:43

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.