4 cos² x - 3 = 0
4 cos² x = 3
cos² x = 3/4
cos x = ±(√3)/2
Fixing the squared cosine doesn't discriminate among quadrants. There's one in every quadrant
cos x = ± cos(π/6)
Let's do plus first. In general, cos x = cos a has solutions x = ±a + 2πk integer k
cos x = cos(π/6)
x = ±π/6 + 2πk
Minus next.
cos x = -cos(π/6)
cos x = cos(π - π/6)
cos x = cos(5π/6)
x = ±5π/6 + 2πk
We'll write all our solutions as
x = { -5π/6, -π/6, π/6, 5π/6 } + 2πk integer k
What we want to do first is isolate the variable. To do this we need to multiply each side by 5 to remove the fraction
5 * 5 = 5*
w
Simplify the right side
5 *
w = 1w
Now simplify the left side
5 * 5 = 25
Then we get...
25 = w
There's your answer!
George Washington
...............
Answer:
0.324
Step-by-step explanation:
Given that :
Success rate = 30%
p = 30% = 0.3
q = 1 - p = 1 - 0.3 = 0.7
Number of trials, n = 6
Probability of having exactly 2 successes ; x = 2
P(x = 2)
Usibgbtge binomial probability relation :
P(x = x) = nCx * p^x * q^(n-x)
P(x = 2) = 6C2 * 0.3^2 * 0.7^4
P(x = 2) = 15 * 0.3^2 * 0.7^4
P(x = 2). = 0.324135
P(x = 2) = 0.324
