Re: How to use inversefunction
- To: mathgroup at smc.vnet.net
- Subject: [mg36205] Re: [mg36189] How to use inversefunction
- From: BobHanlon at aol.com
- Date: Tue, 27 Aug 2002 02:07:12 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
In a message dated 8/26/02 4:39:10 AM, davidol at hushmail.com writes:
> How can I get mathematica to display the inverse of functions like:
>
> f(x) = x^2 - 7*x + 10
>
> or
>
> f(x) = cos(3*x + 1/2*pi)
>
> or
>
> f(x) = (x - 3) / (x + 2)
>
> I'm having trouble getting the syntax right.
>
Solve[y==x^2-7*x+10, x]
{{x -> (1/2)*(7 - Sqrt[9 + 4*y])}, {x -> (1/2)*(7 + Sqrt[9 + 4*y])}}
x^2-7*x+10 /. % // ExpandAll
{y, y}
Solve[y == Cos[3*x+1/2*Pi], x]
{{x -> -(ArcSin[y]/3)}}
Cos[3*x+1/2*Pi] /. %
{y}
Solve[y == (x-3)/(x+2), x]
{{x -> (-3 - 2*y)/(-1 + y)}}
(x-3)/(x+2) /. % // Simplify
{y}
Bob Hanlon
Chantilly, VA USA