       NIntegrate & Integrate

• To: mathgroup at smc.vnet.net
• Subject: [mg100048] NIntegrate & Integrate
• From: Konstantin <kzhuravl at mtu.edu>
• Date: Fri, 22 May 2009 01:47:50 -0400 (EDT)

```Hello everybody,

Easy question for Mathematica. Evaluate definite integral: 2*Cos[x] from 8.76 to 4.56.

I have evaluated it three different ways: Integrate, NIntegrate and Integral sign from basic math input palette.

Here is the code(without Integral sign from basic math input palette):

Clear[x]
{a, b} = {8.76, 4.56};
NIntegrate[2*Cos[x], {x, a, b}]
Clear[x]
Integrate[2*Cos[x], {x, a, b}]

My output is:

3.21059(NIntegrate)
-3.21059(Integrate)

The right answer is -3.21059.

Why does NIntegrate gave me wrong answer? Any help is appreciated. Thanks

Konstantin

```

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