Question

I don’t understand how to do this

Answer 1

Answer:

The solution is $x =0.$

Step-by-step explanation:

The equation

$\bold{(1).}\: sin(\dfrac{3\pi }{2} +x)+sin(\dfrac{3\pi }{2} +x) =-2$

can be rewritten as

$2* sin(\dfrac{3\pi }{2} +2) =-2$

and can be further simplified to

$sin(\dfrac{3\pi }{2}+x ) =-1$.

Now, taking the inverse sine of both sides we get:

$sin^{-1}(sin(\dfrac{3\pi }{2} +x) =sin^{-1}(-1)$

$\bold{(2).}\: \dfrac{3\pi }{2} +2 =sin^{-1}(-1)$

The value of the right side on the interval $[0,2\pi)$ is

$sin^{-1}(-1) = \dfrac{3\pi}{2} \: \:( \text{or }270^o)$ ,

which makes the equation (2)

$\dfrac{3\pi }{2}+x =\dfrac{3\pi}{2}$

solving for $x$ gives

$\boxed{x = 0}$

which is our solution.