       • To: mathgroup at smc.vnet.net
• Subject: [mg56215] Re: Integrate is driving me crazy, please help!
• From: Helen Read <hpr at together.net>
• Date: Tue, 19 Apr 2005 04:55:33 -0400 (EDT)
• References: <d3vn1h\$jm9\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```Jim Martin wrote:
> Hello Mathematica Experts:
>
> I am a biomechanist and work mostly in the area of muscle contraction. I
> do a lot of numerical computations using excel, but right now I need an
> analytical solution that represents force as a function of position
> integrated over a shortening amplitude. I downloaded a trial version of
> Mathematica and have tried to obtain a solution for this:
>
> Integrate[(hillb*((f0 + hilla)/(2*pi*f*a*Cos(ArcSin(x/a)) + hillb))) -
> hilla, {x, -a, a}]

The number pi is denoted Pi in Mathematica. Remember that *all* built-in
functions, constants, etc., begin with a capital letter.

And argument(s) of a function are always enclosed within square
brackets. f[x], Sin[x], Log[x], etc.

So what you need is the following.

Integrate[(hillb*((f0 + hilla)/(2*Pi*f*a*Cos[ArcSin[x/a]] + hillb))) -
hilla, {x, -a, a}]

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