# Thread: Find all the solutions (Inverse Trig Funct.)

1. ## Find all the solutions (Inverse Trig Funct.)

$5 cos (x + 3) = 1$

Thank you!

2. Treat it like a regular algebra problem.

Here's a hint, there will be division and an inverse function.

3. 1. Divide 5
2. Arc Cosine
3. Subtract 3
4. Answer is -1.63 (the first solution)

However the solution page shows 1.914 and 4.653.

4. $5 \cos (x + 3) = 1$

$\cos(x + 3) = \frac{1}{5}$

$\arccos(\cos(x + 3)) = \arccos(\frac{1}{5})$

$x + 3 = \arccos(\frac{1}{5})$

$x = \arccos(\frac{1}{5}) - 3$

$x \approx -1.63$

Yeah ... there's something not right there, are you sure you checked the right solutions against the exercise ?