Instructions
Begin with the general trigonometric sine function "f(x) = a*sin(bx + c) + d" where a, b, c and d are known constants and x is a variable.
Add a constant value to the x value within the sine function. For example, "f(x) = a*sin(bx + c) + d = sin(x + c)" when "a = 1," "b = 1" and "d = 0." Adding "c = 6" to the x value within the function phase shifts the sine function "6" units to the left and the sine equation becomes: "f(x) = sin(x + 6)."
Subtract a constant value from the x value within the sine function. For example, "f(x) = a*sin(bx + (-c)) + d = sin(x + (-c))" when "a = 1," "b = 1" and "d = 0." Subtracting "c = 6" from the x value within the function phase shifts the sine function "6" units to the right and the sine equation becomes: "f(x) = sin(x + (-6)) = sin(x - 6)."
Multiply the x variable by a constant to compress or stretch the graph of the sine function, depending on the sign of the constant. For example, the sine function "f(x) = sin(2x + 6)" stretches the function by a factor of "2" and phase shifts it to the left "6" units, thereby increasing the function's period. The function "f(x) = sin(-2x + 6)" compresses the function by a factor of "2" and phase shifts it to the right "6" units.