Question

Solve the follow equation in Radians to two decimal places.

3cos x/2 +1 = 0

Answer 1

@Hero

Answer 2

Is this your problem?\[3\cos(\frac{ x }{ 2 })+1=0\]

Answer 3

Yes

Answer 4

@BlixFace

Answer 5

The first step is to move everything that you can to the right side.
\[\cos \left( \frac{ x }{ 2 } \right)=-\frac{ 1 }{ 3 }\]Now we find where inverse cosine is -1/3, which is 1.9106
\[\ \left( \frac{ x }{ 2 } \right)=1.9106+2k \pi\]
Next step is to get rid of the 2 inside the parenthesis.
\[x=2(1.9106+2k \pi )\rightarrow 3.8212+4k \pi\]
\[\theta=3.82+4k \pi\]

Answer 6

@blixface where does the 2kπ
come from?

Answer 7

It's to express all solutions for cosine. You can try to review your textbook for solving trigonometric equations for a more detailed explanation.