$\bf cos^2(x)+2cos(x)+1=0\implies \stackrel{\textit{let's notice, this is simply }ax^2+bx+c=0}{[cos(x)]^2+2cos(x)+1=0} \\[2em] [cos(x)+1][cos(x)+1]=0 \\\\[-0.35em] ~\dotfill\\\\ cos(x)+1=0\implies cos(x)=-1\implies x=cos^{-1}(-1)\implies \stackrel{\textit{for the range }[0,2\pi ]}{x=\pi } \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ ~\hfill \stackrel{\textit{all solutions}}{x=\pi +2\pi n~~,~~ n \in \mathbb{Z}}~\hfill$

6 0

3 years ago

The circumstance of a circle is 36pi inches what is the radius for this circle

frez [133]

Circumference = 2pi*r

r = radius

In our problem,

circumference = 36pi

r = ?

Let's plug our values into the formula above.

36pi = 2pi * r

Divide both sides by 2pi

18 = r

4 0

3 years ago

What’s the answer pls

MAXImum [283]

37.1
35 * .06 = 2.1
35 + 2.1 = 37.1

8 0

3 years ago

in a test +3 marks are given for every correct answer and -1 for every incorrect answer Mary attempted all questions and scored

AVprozaik [17]

Answer:

Step-by-step explanation:

correct c=3 x 10

incorrect i=-1

-------

3c-i=20
3*10-i=20
i=10

incorrect= 10

number of questions= 10+10= 20

7 0

3 years ago