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2 years ago

What is the explicit formula for the sequence: 18, 11, 4, -3?

Mathematics

1 answer:

kumpel [21]2 years ago

7 0

Answer:

Step-by-step explanation:

c.d. d=11-18=4-11=-7

y=18+(n-1)(-7)

or y=18-7n+7

or y=25-7n

n=1,2,3, ...

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Thomas deposited $800 into two different accounts.

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2 years ago

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2 years ago

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An order form from least to greatest with these numbers 2.07,2 an 7/10,2.67 -2.67

olganol [36]

Answer:

Step-by-step explanation:

-2.67

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2 years ago

Which of the following functions are solutions of the differential equation y'' + y = 3 sin x? (select all that apply)

DiKsa [7]

Answer:

Step-by-step explanation:

We must compute the derivatives and check if the equation is satisfied.

A. $y'=(3\sin x)'=3\cos x$ . Differentiate again to get $y''=(3\cos x)'=-3\sin x$ , then $y''+y=-3\sin x+3\sin x=0\neq 3\sin x$ so this choice of y doesn't solve the equation.

B. $y'=3\sin x+3x\cos x-5\cosx +5x\sin x=(5x+3)\sin x+(3x-5)\cos x$ and $y''=5\sin x+(5x+3)\cos x+3\cos x-(3x-5)\sin x=(10-3x)\sin x+(5x+6)\cos x$ , then $y''+y=10\sin x+6\cos x\neq 3\sin x$ so y is not a solution

C. $y'=\frac{-3}{2}\cos x+\frac{3}{2}x\sin x$ hence $y''=\frac{3}{2}\sin x+\frac{3}{2}\sin x+\frac{3}{2}x\cos x=3\sin x+\frac{3}{2}x\cos x$ . Then $y''+y=3\sin x+\frac{3}{2}x\cos x-\frac{3}{2}x\cos x=3\sin x$ so y is a solution.

D. $y'=-3\sin x$ and $y''=-3\cos x$ , then $y''+y=0$ thus y isn't a solution

E. $y'=\frac{3}{2}\sin x+\frac{3}{2}x\cos x$ hence $y''=\frac{3}{2}\cos x+\frac{3}{2}\cos x-\frac{3}{2}x\sin x=3\cos x-\frac{3}{2}x\cos x$ . Then $y''+y=3\cos x-\frac{3}{2}x\cos x-\frac{3}{2}x\cos x=3\cos x\neq 3\sin x$ then y is not a solution.

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2 years ago

Keisha is solving the equation 7^x=9.

olganol [36]

$\bf \textit{Logarithm of exponentials}\\\\
log_a\left( x^ b \right)\implies b\cdot log_a(x)\\\\
-------------------------------\\\\
7^x=9\implies \boxed{log(7^x)=log(9)}\implies x\cdot log(7)=log(9)
\\\\\\
x=\cfrac{log(9)}{log(7)}$

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2 years ago