I'll try it.
I just went through this twice on scratch paper. The first time was to
see if I could do it, and the second time was because the first result
I got was ridiculous. But I think I got it.
You said <span><u>3sin²(x) = cos²(x)</u>
Use this trig identity: sin²(x) = 1 - cos²(x)
Plug it into the original equation for (x).
3(1 - cos²(x) ) = cos²(x)
Remove parentheses on the left: 3 - 3cos²(x) = cos²(x)
Add 3cos²(x) to each side: 3 = 4cos²(x)
Divide each side by 4 : 3/4 = cos²(x)
Take the square root of each side: <em>cos(x) = (√3) / 2</em> .
There it is ... the cosine of the unknown angle.
Now you just go look it up in a book with a table cosines,
or else pinch it through your computer or your calculator,
or else just remember that you've learned that
cos( <em><u>30°</u></em> ) = </span><span><span>(√3) / 2 </span>.
</span>
Answer: The fourth one
Step-by-step explanation:
The answer should be 25.12
This is the answer i got 147
X^2 - 6x = 20
x^2 - 6x + 9 = 20 + 9
(x - 3)^2 = 29
x - 3 = (+-) sqrt 29
x = 3 (+-) sqrt 29
x = 3 (+-) 5.39
x = 3 + 5.39 = 8.39 <=
x = 3 - 5.39 = - 2.39 <=
