trigs graph and solution

Great444

14

What is the strategy to solve trigs and find solutions within the range, I only can find solutions from the graph.

Reply 1

MindMax2000

Universities Forum Helper

22

Original post by Great444

What is the strategy to solve trigs and find solutions within the range, I only can find solutions from the graph.

Should I presume this is A Level Maths? It's a little difficult to tell.

If you want to solve trigs, they normally present the question in the form of an equation for you to solve. Once you have got your answer down, I would normally sketch out a graph within the particular ranges to find the relevant answers.
Even if you are able to get the answer in your head, I would still sketch out the graphs to check, since it's difficult to visualise the graphs in your head (and hence liable to make mistakes) especially when you're under time (and other types of) pressure.

Reply 2

Great444

OP

14

Original post by MindMax2000

Should I presume this is A Level Maths? It's a little difficult to tell.

If you want to solve trigs, they normally present the question in the form of an equation for you to solve. Once you have got your answer down, I would normally sketch out a graph within the particular ranges to find the relevant answers.
Even if you are able to get the answer in your head, I would still sketch out the graphs to check, since it's difficult to visualise the graphs in your head (and hence liable to make mistakes) especially when you're under time (and other types of) pressure.

I tried with CAST circle and applying the rules ?

Reply 3

mqb2766

21

Original post by Great444

I tried with CAST circle and applying the rules ?

Its the "same" whether you use cast or use the appropriate sinusoidal curve. So for instance, cos() is symmetric about 0 and 180 which means there is a second solution reflected in the x-axis (positive x-axis corresponds to reflection about 0 and negative x-axis corresponds to a reflection about 180).

What problem are you having?