c1 solomon paper c

Just doing some revision - not sure what it means exactly with question 8 from paper c - c1 solomon papers.

Figure one shows the graph of y = f(x)

Write down the number of solutions that exist for the equation

f(x) = 1

f(x) = - x

Answer in the mark scheme say 3 and 1 respectively but just not sure what the questions means....

Must be something simply because its only worth two marks. ..

Reply 1

Fish40

18

Original post by christinajane

Just doing some revision - not sure what it means exactly with question 8 from paper c - c1 solomon papers.

Figure one shows the graph of y = f(x)

Write down the number of solutions that exist for the equation

f(x) = 1

f(x) = - x

Answer in the mark scheme say 3 and 1 respectively but just not sure what the questions means....

Must be something simply because its only worth two marks. ..

You dont understand it, f(x)=1, whats f(x) and when it equals 1, how many solutions or points are there , and same for the next one, figure it out :wink:

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Reply 2

christinajane

OP

4

Its a bit of a funny graph - doesn't give you f(x)

It touches the x axis at -2 and 2 - so I thought f(x) = (x-2)(x+2) or (x-4)^2

But the graph isn't a curve so its kinda throwing me little - hmmm

Reply 3

Ishan_2000

18

Original post by christinajane

Its a bit of a funny graph - doesn't give you f(x)

It touches the x axis at -2 and 2 - so I thought f(x) = (x-2)(x+2) or (x-4)^2

But the graph isn't a curve so its kinda throwing me little - hmmm

f(x) is the same as writing 'y', so all you do is draw the line f(x) = 1, otherwise known as y=1 on the graph they give you, then see how many times the line y=1 crosses the line drawn on the graph. This is the number of solutions you are looking for.

Do the same for f(x) = -x

Reply 4

christinajane

OP

4

Ahhh yes!

I thought I had to figure out f(x) by looking at the graph, because it doesn't give you f(x) - expand brackets etc equate it to one and find the solutions that way... over complicating matters

(edited 7 years ago)

Reply 5

Ishan_2000

18

Original post by christinajane

Ahhh yes!

I thought I had to figure out f(x) by looking at the graph, because it doesn't give you f(x) - expand brackets etc equate it to one and find the solutions that way... over complicating matters