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Calculus, MET1 2016 VCAA 6a

Let  `f : [-pi,  pi] → R`, where  `f (x) = 2 sin (2x)-1`.

Calculate the average rate of change of  `f` between  `x = -pi/3`  and  `x = pi/6`.   (2 marks)

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`(4sqrt3)/pi`

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`text(Average rate of change)`

`= (f(pi/6)-f(-pi/3))/(pi/6-(-pi/3))`

`= [(2sin(pi/3)-1)-(2sin(-(2pi)/3)-1)] xx 2/pi`

`= [(2 xx (sqrt3)/2-1)-(2 xx (-sqrt3)/2-1)] xx 2/pi`

♦ Mean mark 48%.
MARKER’S COMMENT: Evaluating  `f(-pi/3)` caused significant problems here.

`= (sqrt3-1 + sqrt3 + 1) xx 2/pi`

`= (4sqrt3)/pi`

 

 

Filed Under: Differentiation (Trig), Trig Differentiation Tagged With: Band 5, smc-736-80-Average ROC, smc-744-10-sin, smc-744-80-Average ROC

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