13pi/12 lies between pi and 2pi, which means sin(13pi/12) < 0
Recall the double angle identity,
sin^2(x) = (1 - cos(2x))/2
If we let x = 13pi/12, then
sin(13pi/12) = - sqrt[(1 - cos(13pi/6))/2]
where we took the negative square root because we expect a negative value.
Now, because cosine has a period of 2pi, we have
cos(13pi/6) = cos(2pi + pi/6) = cos(pi/6) = sqrt[3]/2
Then
sin(13pi/12) = - sqrt[(1 - sqrt[3]/2)/2]
sin(13pi/12) = - sqrt[2 - sqrt[3]]/2
Answer:
1 ± i(1/2)√2
Step-by-step explanation:
Write this quadratic in standard form: subtract 3 from both sides. This results in 2x^2 - 4x - 3 = 0. Let's apply the quadratic formula. The coefficients of the x terms are 2, -4 and -3, so the discriminant is (-4)^2 - 4(2)(-3), or 16 - 24 = -8.
Following the format of the quadratic formula, we get
-(-4) ±i2√8 4 ±i2√2
x = ----------------- = --------------- = 1 ± i(1/2)√2
4 4
Answer:
No, the rock will not hit the water in 2 second but it will hit the water in t ≅ 2.17 second
Step-by-step explanation:
Let the distance be s in feet. i.e, 
where t is in second.
You drop a rock from a bridge that is 75 feet above the water.
Use the expression 
to solve for t:
Given: s =75 feet
then, substitute in the above expression:
or we can write it as:
or
⇒ t = 2.16506351 or t ≅2.17 second
Therefore, the rock hit the water in t≅2.17 second
Answer:
18
Step-by-step explanation:
11 * 2 = 22
9 * 2 = 18
