# past paper question (encounter problems)

• Mar 18th 2012, 02:28 PM
mathkid12
past paper question (encounter problems)
Given that delta (Δ) is an acute angle such that cos delta(Δ)= 1/4x
find the expression for sin 2delta(Δ) in terms of x

how to do such a question??????
• Mar 18th 2012, 02:57 PM
skeeter
Re: past paper question (encounter problems)
Quote:

Originally Posted by mathkid12
Given that delta (Δ) is an acute angle such that cos delta(Δ)= 1/4x
find the expression for sin 2delta(Δ) in terms of x

how to do such a question??????

$\cos(\Delta) = \frac{1}{4x}$ or $\frac{1}{4} x$ ???
• Mar 18th 2012, 03:00 PM
mathkid12
Re: past paper question (encounter problems)
second one, 1/4 x (sorry i cant type the equations properly i dont know how??)
• Mar 18th 2012, 03:11 PM
Plato
Re: past paper question (encounter problems)
Quote:

Originally Posted by mathkid12
second one, 1/4 x (sorry i cant type the equations properly i dont know how??)

Then $\sin(\Delta)=\sqrt{1-\frac{x^2}{16}}$

Learn some basic LaTeX.
[TEX]\cos(\Delta)=\frac{x}{4}[/TEX] gives $\cos(\Delta)=\frac{x}{4}$.
• Mar 18th 2012, 03:50 PM
mathkid12
Re: past paper question (encounter problems)
thanks alot