Trigonometry

Hi could Someone help me with a question..............

It is on page 92, question 13 in the c3 book

Cheers :biggrin:

Sorry i couldnt be asked to type out the question sos!

that really depends on what c3 book you have. im guessing most people wont have exactly the same book as you so youll probably get some help if you do bother writing out the question . . .

Reply 2

vaider

sec^2x-2√3/3tanx-2=0

The interval is between 0 and 2pi............

Thanks help would be most appreciated! :biggrin:

Reply 3

Michael Scofield

If the question is from the Heinemann Modular Mathematics Core 3 text book, then here is the result. The question is sec^2 x - (2root3/3)tan x - 2 = 0, in interval 0 upto and including 2pi. Solutions are given by:

sec^2 x - (2root3/3)tan x - 2 = 0
1 + tan^2 x - (2root3/3)tan x - 2 = 0
tan^2 x - (2root3/3)tan x - 1 = 0

Let tan x = x (for aesthetic purposes),
x^2 - (2root3/3)x - 1 = 0

Use the quadratic fomulae for the above equation to get two solutions in tan x, which are tan x = 1.732050808, or tan x = -0.577350269

Therefore, x = 60 degrees, or x = -30 degrees.

Solutions, (using the ASTC method or otherwise) are:
x = 60, 150, 240, 330
x = pi/3, 5pi/6, 4pi/3, or 11pi/6

done diddly done