If x=1+√2, evaluate x³+1/x³.

Mathematics

1 answer:

aleksandr82 [10.1K]2 years ago

3 0

Answer:

10√2

Step-by-step explanation:

If x=1+√2, evaluate x³+1/x³

--------

x³+1/x³= (x+1/x)(x²-x*1/x+1/x²)=(x+1/x)(x²+1/x²+2-3)= (x+1/x)((x+1/x)²-3)
x+1/x= 1+√2 + 1/(1+√2)= 1+√2+(1-√2)/(1-√2)(1+√2)= 1+√2 - (1-√2)= 2√2
x³+1/x³= 2√2((2√2)²-3)= 2√2(8-3)= 10√2

You might be interested in

Find the values for c and d

baherus [9]

Answer:

c=-5

d=1

Step-by-step explanation:

$(cy^2)(4y^d)=-20y^3$

I'm going to reorder the left-hand side. Multiplication is commutative.

$(4c)(y^2y^d)=-20y^3$

Since the bases are the same in $y^2y^d$ and the operation is multiplication, I'm going to add the exponents giving me:

$4cy^{2+d}=-20y^3$

So this implies we have two equations to solve:

$4c=-20$ and $2+d=3$

So the first equation can be solved by dividing both sides by 4 giving you $c=-5$ .

The second equation can be solved by subtracting 2 on both sides giving you $d=1$ .

6 0

2 years ago

Eq 1 X+Y=16 <br> Eq 2 6x+9y=120<br><br> Solve by substitution <br> Solve step by step

Alexxx [7]

Answer:

X = 8, Y = 8

Step-by-step explanation:

Step 1) Solve for Y w/ bottom equation to yield - y = -2/3x + 40/3.

Step 2) substitute equation into x + y = 16 to get 1/3x + 40/3 = 16 multiply by 3 to clear the fractions and get x + 40 = 48 - subtract 40 by both sides to get x = 8.

Step 3) Plug x = 8 into the bottom equation to get 48 + 9y = 120, subtract 48 by both sides to get 9y = 72 and then divide by 9. The product is y = 8.

7 0

1 year ago

Use a graphing calculator to graph the function and its parent function. Then describe the transformations, f(x)=(x+3)+1/4

nlexa [21]

Most of the graphing resources used shows that the graph is translated up by 3.25 (3 + 1/4). If you add the 3 and the 1/4, you get the equation of a line:

f(x) = x + 3.25,

which means that the graph of f(x)= x now has a y intercept of 3.25.

The graphs are below. The red line represents f(x) = x, and the green line represents (x+3)+1/4. Hope this helps!