# [✓] Plot two equations and find the intersection point?

Posted 9 months ago
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 Does anyone know how to plot these two equations x=cos x in the interval [0,[Pi]/2] and find the intersection point. Please help
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Posted 9 months ago
 Hi Lexie,I am not quite sure what you mean by "two equations", where you only give x=cosx. In theory this can be plotted using: Plot[{x, Cos[x]}, {x, -1, 3}] There are various ways to solve this. For example: FindRoot[x == Cos[x], {x, 1}] (*{x -> 0.739085}*) or NSolve[{x == Cos[x] && x > 0 && x < Pi/2}, x] (*{{x -> 0.739085}}*) Cheers,Marco
Posted 9 months ago
 Thank you so much!! Do you know how to plot these two equations sin(e^x)=x^2-1 in the interval [0,2] and find the intersection points???
Posted 9 months ago
 I tried exactly what I did for the first one just switched out the equations but it appears that only the x^2 -1 equation is showing up on the graph.
Posted 9 months ago
 Also does anyone know how to plot these two equations sin(e^x)=x^2-1 in the interval [0,2] and find the intersection points???
Posted 9 months ago
 Also does anyone know how to plot these two equations sin(e^x)=x^2-1 in the interval [0,2] and find the intersection points???
Posted 9 months ago
 Also does anyone know how to plot these two equations sin(e^x)=x^2-1 in the interval [0,2] and find the intersection points???
Posted 9 months ago
 The procedure is identical to the one outlined above! What have you tried? Even if you type your question just "as is" into WolframAlpha it works:http://www.wolframalpha.com/input/?i=sin(e%5Ex)%3Dx%5E2-1Cheers,Marco
Posted 9 months ago
 I tried exactly what I did for the first one just switched out the equations but it appears that only the x^2 -1 equation is showing up on the graph.
Posted 9 months ago
 How did you do that: Plot[{Sin[E^x], x^2 - 1}, {x, 0, 2}] Cheers,MarcoPS: Note that the E needs to be capital.
Posted 9 months ago
 This is what I tried Plot[{sin[e^x], x^2 - 1}, {x, 0, 2}]
Posted 9 months ago
 Yes, that won't work. In Mathematica all functions start with a capital letter. Hence, sin needs to be Sin. Also the "e" is just a variable without any fixed value. If you mean the basis of the exponential function you will have to use E. If you do not stick to the basic syntactic rules Mathematica will not evaluate.IF you are not sure about how to type it in, you can also use "natural language input", i.e. you type a single "=" sign at the beginning of a line:In many cases that fixes any syntactic errors.Cheers,MarcoBest wishes, Marco