Solving graphically

[BakerDad12]

Hi guys, when solving graphically how accurate do we have to be? There are some questions from my textbook that tell you to graph an equation and then solve it graphically. I have attached a question from the textbook below.

My question is, how accurate does the solving graphically part have to be? Our teacher says it's ok to approximate as graphs aren't always exact. Is this alright, or should we work out each value algebraically and then plot the points? Doing this method isn't really solving it graphically though.


Thank you very much!

[RuiAce]

To be honest, about as accurate as your ruler can handle it. If this means only to 1 decimal place, then unfortunately so be it.

In the exam, for those kinds of questions they'll usually tell you how good the approximation needs to be. Provided your sketch is accurate enough, and your measurements reflect your sketch, they can't penalise you much here.

(Alternatively, they may just provide the sketch for you on grid paper - see the sample paper for Maths Advanced. But they'll still tell you how good your approximation needs to be.)

Pretty much, I'm in agreement with what your teacher said here.