# trig equation

• Feb 22nd 2011, 06:15 AM
loraltmath
trig equation
Solve the equation 4 + 3 sin (2x – 1) = 6 for 0 < x < pi/2. please help me solve this equation
• Feb 22nd 2011, 06:26 AM
Prove It
$\displaystyle \displaystyle 4 + 3\sin{(2x-1)} = 6$

$\displaystyle \displaystyle 3\sin{(2x-1)} = 2$

$\displaystyle \displaystyle \sin{(2x-1)} = \frac{2}{3}$

$\displaystyle \displaystyle 2x-1 = \arcsin{\left(\frac{2}{3}\right)}$

$\displaystyle \displaystyle 2x = 1 + \arcsin{\left(\frac{2}{3}\right)}$

$\displaystyle \displaystyle x = \frac{1}{2} + \frac{1}{2}\arcsin{\left(\frac{2}{3}\right)}$
• Feb 22nd 2011, 06:27 AM
Plague01
Quote:

Originally Posted by loraltmath
Solve the equation 4 + 3 sin (2x – 1) = 6 for 0 < x < pi/2. please help me solve this equation

sin(2x-1)=2/3

2x-1=arcsin(2/3)

solve for x make sure calc is in radians
• Feb 22nd 2011, 07:06 AM
loraltmath
Quote:

make sure calc is in radians
thank you, but how do i do this?
• Feb 23rd 2011, 03:30 AM
HallsofIvy
Quote:

Originally Posted by loraltmath
thank you, but how do i do this?

Are you saying that you do not know what "radians" are? Do you understand what the condition you stated, "$\displaystyle 0\le x\le \pi/2$" means?

If you are using a calculator to find arcsin(2/3), do you know how to set the "mode" of your calculator? For example, the calculator that comes with Windows has buttons that give "Degrees", "Radians", and "Grad".