Answer:
Is the answer B?
Step-by-step explanation:
The angle between the planes is the same as the angle between their normal vectors, which are
<em>n</em><em>₁</em> = ⟨1, 1, 1⟩
<em>n</em><em>₂</em> = ⟨4, 3, 1⟩
The angle <em>θ</em> between the vectors is such that
⟨1, 1, 1⟩ • ⟨4, 3, 1⟩ = ||⟨1, 1, 1⟩|| ||⟨4, 3, 1⟩|| cos(<em>θ</em>)
Solve for cos(<em>θ</em>) :
4 + 3 + 1 = √(1² + 1² + 1²) √(4² + 3² + 1²) cos(<em>θ</em>)
8 = √3 √26 cos(<em>θ</em>)
cos(<em>θ</em>) = 8/√78
Answer:
C) x2 + x = 306
Step-by-step explanation:
x2 + x = 306
x2 + x - 306 = 0
x2 + 18x - 17x + 18 * (-17) = 0
x ( x + 18) - 17 (x +18) =0
(x + 18) (x - 17 ) = 0
x = -18 or 17
The solution to the given differential equation is yp=−14xcos(2x)
The characteristic equation for this differential equation is:
P(s)=s2+4
The roots of the characteristic equation are:
s=±2i
Therefore, the homogeneous solution is:
yh=c1sin(2x)+c2cos(2x)
Notice that the forcing function has the same angular frequency as the homogeneous solution. In this case, we have resonance. The particular solution will have the form:
yp=Axsin(2x)+Bxcos(2x)
If you take the second derivative of the equation above for yp , and then substitute that result, y′′p , along with equation for yp above, into the left-hand side of the original differential equation, and then simultaneously solve for the values of A and B that make the left-hand side of the differential equation equal to the forcing function on the right-hand side, sin(2x) , you will find:
A=0
B=−14
Therefore,
yp=−14xcos(2x)
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