Solve for <em>x</em> when √(<em>x</em> ² - 4) = 1 :
√(<em>x</em> ² - 4) = 1
<em>x</em> ² - 4 = 1
<em>x</em> ² = 5
<em>x</em> = ±√5
We're looking at <em>x </em>≤ 0, so we take the negative square root, <em>x</em> = -√5.
This means <em>f</em> (-√5) = 1, or in terms of the inverse of <em>f</em>, we have <em>f</em> ⁻¹(1) = -√5.
Now apply the inverse function theorem:
If <em>f(a)</em> = <em>b</em>, then (<em>f</em> ⁻¹)'(<em>b</em>) = 1 / <em>f '(a)</em>.
We have
<em>f(x)</em> = √(<em>x</em> ² - 4) → <em>f '(x)</em> = <em>x</em> / √(<em>x</em> ² - 4)
So if <em>a</em> = -√5 and <em>b</em> = 1, we get
(<em>f</em> ⁻¹)'(1) = 1 / <em>f '</em> (-√5)
(<em>f</em> ⁻¹)'(1) = √((-√5)² - 4) / (-√5) = -1/√5
The sign must be negative; see the attached plot, and take note of the negatively-sloped tangent line to the inverse of <em>f</em> at <em>x</em> = 1.
Answer:
0.1
Step-by-step explanation:
0.1
I just put it into a calculator
Answer:
(155.301 ; 159.299)
Step-by-step explanation:
Xbar = 157.3
Sample size, n = 234
Population standard deviation, σ = 15.6
The confidence interval :
Xbar ± standard Error
Standard Error = Zcritical * σ/√n
Zcritical at 95% = 1.96
Standard Error = 1.96 * (15.6/√234) = 1.999
Lower boundary : 157.3 - 1.999 = 155.301
Upper boundary : 157.3 + 1.999 = 159.299
(155.301 ; 159.299)
450 + 64% = 738.
738 - 450 = 288
or
64% x 450 = 288
288 more children joined the league this year than last year.