What is 10+10 hmmmmmmmm

Solve the quadratic equation (2x+5)(2x-5)

mote1985 [20]

If you want to multiply (2*x + 5) and (2*x - 5), you can do this using the following steps:

(2*x + 5) * (2*x - 5) = 4*x^2 - 10*x + 10*x - 25 = 4*x^2 - 25

The correct result is 4*x^2 - 25.

4 0

3 years ago

All vectors are in Rn. Check the true statements below:

Oduvanchick [21]

Answer:

A), B) and D) are true

Step-by-step explanation:

A) We can prove it as follows:

$Proy_{cv}y=\frac{(y\cdot cv)}{||cv||^2}cv=\frac{c(y\cdot v)}{c^2||v||^2}cv=\frac{(y\cdot v)}{||v||^2}v=Proy_{v}y$

B) When you compute the product Ax, the i-th component is the matrix of the i-th column of A with x, denote this by Ai x. Then, we have that $||Ax||=\sqrt{(A_1 x)^2+\cdots (A_n x)^2}$ . Now, the colums of A are orthonormal so we have that (Ai x)^2=x_i^2. Then $||Ax||=\sqrt{(x_1)^2+\cdots (x_n)^2}=||x||$ .

C) Consider $S=\{(0,2),(2,0)\}\subseteq \mathbb{R}^2$ . This set is orthogonal because $(0,2)\cdot(2,0)=0(2)+2(0)=0$ , but S is not orthonormal because the norm of (0,2) is 2≠1.

D) Let A be an orthogonal matrix in $\mathbb{R}^n$ . Then the columns of A form an orthonormal set. We have that $A^{-1}=A^t$ . To see this, note than the component $b_{ij}$ of the product $A^t A$ is the dot product of the i-th row of $A^t$ and the jth row of $A$ . But the i-th row of $A^t$ is equal to the i-th column of $A$ . If i≠j, this product is equal to 0 (orthogonality) and if i=j this product is equal to 1 (the columns are unit vectors), then $A^t A=I$

E) Consider S={e_1,0}. S is orthogonal but is not linearly independent, because 0∈S.

In fact, every orthogonal set in R^n without zero vectors is linearly independent. Take a orthogonal set $\{u_1,u_2\cdots u_p\}$ and suppose that there are coefficients a_i such that $a_1u_1+a_2u_2\cdots a_nu_n=0$ . For any i, take the dot product with u_i in both sides of the equation. All product are zero except u_i·u_i=||u_i||. Then $a_i||u_i||=0$ then $a_i=0$ .

5 0

3 years ago

COMO SE SACA UNA TABLA DE FRECUENCIA?????=? URGENTE ES PA HOY

xz_007 [3.2K]

Answer:

Para construir una tabla de frecuencias, procedemos de la siguiente manera:

Construye una tabla con tres columnas. La primera columna muestra lo que se organiza en orden ascendente (es decir, las marcas). ...

Repase la lista de marcas. ...

Cuente el número de marcas de conteo para cada marca y escríbalo en la tercera columna.

8 0

2 years ago

Write the sentence as an equation. 16 equals 392 multiplied by k

Natasha2012 [34]

Answer:

The answer to your question is: 392 × k =16

5 0

2 years ago

Answer please i am literally crying because i will get in trouble if i dont do it

alekssr [168]

Convert percentages to units.
100% - 20% = 80% = 0.8
100% - 25% = 75% = 0.75

Then multiply those together:
0.8*0.75=0.6=60%

100% - 60% = 40%. That's the overall price percentage reduction.

P.S. You can convert percentages to units by diving % by 100 for example 100% divided by 100 is equal to 1.
And vice versa aka multiply units by 100 and you get %, for example 0.8 times 100 is 80%

3 0

3 years ago

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