Answer:
3490 decigram
Step-by-step explanation:

With ϕ ≈ 1.61803 the golden ratio, we have 1/ϕ = ϕ - 1, so that
![I = \displaystyle \int_0^\infty \frac{\sqrt[\phi]{x} \tan^{-1}(x)}{(1+x^\phi)^2} \, dx = \int_0^\infty \frac{x^{\phi-1} \tan^{-1}(x)}{x (1+x^\phi)^2} \, dx](https://tex.z-dn.net/?f=I%20%3D%20%5Cdisplaystyle%20%5Cint_0%5E%5Cinfty%20%5Cfrac%7B%5Csqrt%5B%5Cphi%5D%7Bx%7D%20%5Ctan%5E%7B-1%7D%28x%29%7D%7B%281%2Bx%5E%5Cphi%29%5E2%7D%20%5C%2C%20dx%20%3D%20%5Cint_0%5E%5Cinfty%20%5Cfrac%7Bx%5E%7B%5Cphi-1%7D%20%5Ctan%5E%7B-1%7D%28x%29%7D%7Bx%20%281%2Bx%5E%5Cphi%29%5E2%7D%20%5C%2C%20dx)
Replace
:

Split the integral at x = 1. For the integral over [1, ∞), substitute
:

The integrals involving tan⁻¹ disappear, and we're left with

Answer and Step-by-step explanation:
<u>Trigonometric Function (These only work for right triangles):</u>
SOH-CAH-TOA
S = Sine = sin
C = Cosine = cos
T = Tangent = tan
O = Opposite (side)
H = Hypotenuse (side)
A = Adjacent (side)
SOH = sin(angle) = 
CAH = cos(angle) = 
TOA = tan(angle) = 
1. sinQ (Q is the angle) = 
Use Pythagorean Theorem to find side PQ. 
2. cosQ = 
3. tanQ = 
She spent 20 dollars on each book because if you subtract 18 from 198 you'll get 180 then you divide that by 9 n it leaves you with 20.