2cos^2 x + 3sin x = 0
2(1 - sin^2 x) + 3sin x = 0
2 - 2sin^2 x + 3sin x = 0
2sin^2 x - 3sin x - 2 = 0
Let sin x = m, then
2m^2 - 3m - 2 = 0
2m^2 + m - 4m - 2 = 0
m(2m + 1) - 2(2m + 1) = 0
(m - 2)(2m + 1) = 0
m = 2 or m = -1/2
Now, sin x = -1/2
Therefore, x = 1/6(12nπ - π) and 1/6(12nπ + 7π)
We have 2 denominators that we need to get rid of. Whenever there are the denominators, all we have to do is multiply all whole equation with the denominators.
Our denominators are both 2 and x+1. Therefore, we multiply the whole equation by 2(x+1)
![\frac{x}{2}[2(x+1)]-\frac{2}{x+1}[2(x+1)] = 1[2(x+1)]](https://tex.z-dn.net/?f=%5Cfrac%7Bx%7D%7B2%7D%5B2%28x%2B1%29%5D-%5Cfrac%7B2%7D%7Bx%2B1%7D%5B2%28x%2B1%29%5D%20%3D%201%5B2%28x%2B1%29%5D)
Then shorten the fractions.
![\frac{x}{2}[2(x+1)]-\frac{2}{x+1}[2(x+1)] = 1[2(x+1)]\\x(x+1)-2(2)=1(2x+2)](https://tex.z-dn.net/?f=%5Cfrac%7Bx%7D%7B2%7D%5B2%28x%2B1%29%5D-%5Cfrac%7B2%7D%7Bx%2B1%7D%5B2%28x%2B1%29%5D%20%3D%201%5B2%28x%2B1%29%5D%5C%5Cx%28x%2B1%29-2%282%29%3D1%282x%2B2%29)
Distribute in all.
We should get like this. Because the polynomial is 2-degree, I'd suggest you to move all terms to one place. Therefore, moving 2x+2 to another side and subtract.
We are almost there. All we have to do is, solving for x by factoring. (Although there are more than just factoring but factoring this polynomial is faster.)
Thus, the answer is x = 3, -2
Remark
Make up a proportion that relates the tree and its properties to the stick and its properties.
Givens
Stick height (s_h) = 4
Stick shadow(s_s) = 2
Tree shadow = t_s = 18
Tree height = x
Formula
s_h / s_s = x / t_s
Substitute and solve.
4/2 = x / 18 Cross multiply
4*18 = 2 * x
72 = 2x Divide by 2
72/2 = x
x = 36
The height of the tree is 36 feet.
Answer:
m<c = 104°
m<d = 80°
Step-by-step explanation:
Recall: Opposite angles of a cyclic quadrilateral are supplementary. Therefore, their sum equals 180°. Thus:
m<c + 76° = 180°
m<c + 76° - 76° = 180° - 76° (subtraction property of equality)
m<c = 104°
m<d + 100° = 180°
m<d +100° - 100° = 180° - 100° (subtraction property of equality)
m<d = 80°
Simply divide 650/676=.9615 or 96.15%. So there was 3.85% error
