how to add FANN library in QT Creator in linux
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i'm trying to use fann library in qt environment.i make a project to test a simple example of fann and add 
"LIBS += -L/usr/local/lib -lfann" to ".pro file" but whenever try to run example i countered with this error :

    undefined reference to 'sin'      libfann.so
    undefined reference to 'exp'      libfann.so
    undefined reference to 'log'      libfann.so
    undefined reference to 'cos'      libfann.so
    undefined reference to 'pow'      libfann.so
    undefined reference to 'sqrt'     libfann.so
    undefined reference to 'floor'    libfann.so

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it seems there is a problem with mathematics function,but how should fix it?