I am confused with this equation, can anyone help me find the key points?
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The key points are generally the intercepts, the maximum value, and the minimum value. Your teacher probably asks you to find amplitude, period, phase shift, and vertical shift.
Since 3 is the coefficient of cosine, the amplitude is three. This means that the graph will go up or down three units from the middle value (it will start at (-3, -1), which is its maximum value, then go to the middle at -2, then down to it's minimum of -5).
The phase shift is determined by equating bx-c (x+3 in this case) to 0. This means the graph will shift left three units.
The period is determined by taking the coefficient of x and dividing 2(pi) by it. Since x has no coefficient here, the period is 2(pi).
The vertical shift is determined by the d value in the equation y=acos(bx-c)+d. Since it is -2 here, the graph's middle shifts two units down.
Since 3 is the coefficient of cosine, the amplitude is three. This means that the graph will go up or down three units from the middle value (it will start at (-3, -1), which is its maximum value, then go to the middle at -2, then down to it's minimum of -5).
The phase shift is determined by equating bx-c (x+3 in this case) to 0. This means the graph will shift left three units.
The period is determined by taking the coefficient of x and dividing 2(pi) by it. Since x has no coefficient here, the period is 2(pi).
The vertical shift is determined by the d value in the equation y=acos(bx-c)+d. Since it is -2 here, the graph's middle shifts two units down.