help me please Error: L6218E: Undefined symbol (referred from main.o)

Hi, I'm new to stm32(CKS32F103C8T6), copy a code add the address of the libraries,

I'm using Keil uVision5 and compile, but still I get these errors:. 

.\Objects\ebox.axf: Error: L6218E: Undefined symbol InvertedPendulum::getBeamRadian() (referred from main.o).
.\Objects\ebox.axf: Error: L6218E: Undefined symbol InvertedPendulum::getBeamPalstance() (referred from main.o).
.\Objects\ebox.axf: Error: L6218E: Undefined symbol InvertedPendulum::getPendulumRadian() (referred from main.o).
.\Objects\ebox.axf: Error: L6218E: Undefined symbol InvertedPendulum::getPendulumPalstance() (referred from main.o).
.\Objects\ebox.axf: Error: L6218E: Undefined symbol InvertedPendulum::getPendulumAcceleration() (referred from main.o).
.\Objects\ebox.axf: Error: L6218E: Undefined symbol InvertedPendulum::begin() (referred from main.o).
.\Objects\ebox.axf: Error: L6218E: Undefined symbol InvertedPendulum::getMode() (referred from main.o).
.\Objects\ebox.axf: Error: L6218E: Undefined symbol InvertedPendulum::refresh() (referred from main.o).
.\Objects\ebox.axf: Error: L6218E: Undefined symbol InvertedPendulum::setMode(Inverted_Pendulum_Mode_Typedef) (referred from main.o).
.\Objects\ebox.axf: Error: L6218E: Undefined symbol InvertedPendulum::InvertedPendulum(TIM_TypeDef*, TIM_TypeDef*, Gpio*, Gpio*, Gpio*, unsigned, unsigned, float) (referred from main.o).
.\Objects\ebox.axf: Error: L6218E: Undefined symbol vTaskDelay (referred from main.o).
.\Objects\ebox.axf: Error: L6218E: Undefined symbol vTaskStartScheduler (referred from main.o).
.\Objects\ebox.axf: Error: L6218E: Undefined symbol xPortSysTickHandler (referred from main.o).
.\Objects\ebox.axf: Error: L6218E: Undefined symbol xTaskGenericCreate (referred from main.o).

The truth is I don't know how to solve them, please help and say if I did something wrong or I have to explain something.

download the file from here: https://github.com/pidan1231239/inverted_pendulum
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