Vcaa 06 exam 2 question 1c

[Inside Out]

I dnt get vcaa's method of working this question out in the vcaa answers how they ised the period 2pie and than used the intercept. Can someone plz explain

[Vincezor]

I dnt get vcaa's method of working this question out in the vcaa answers how they ised the period 2pie and than used the intercept. Can someone plz explain

I liked this question (embarrassingly, I got it wrong the first time! :S)

I redid this exam very recently, and much to my surprise, I actually got the answer right this time around.

I think it is pretty hard explaining this without using diagrams (sorry, I can't draw!) but I'll try my best.

As you can see from the given image, one of the tangents in above the graph and one is below the graph. Because of this, you cannot simply translate 1 period to the right to obtain the answer of 'm'

Instead what I did was find the equation of the second tangent (the one pictured below the graph) and translated the x intercepts from the first tangent -> second tangent

For the second tangent:
and of course you now the gradient = 1




Using answer from b iii), the other x int is

To find 'm' just subtract one from the other.

m =

Hope that helps!