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3 years ago

Which of the following is equivalent to

Mathematics

2 answers:

Montano1993 [528]3 years ago

8 0

Answer:

Choice B is correct.

Step-by-step explanation:

Given expression is

18-√-25

We have to simplify it.

As we know that

√-a=√-1.√a

Since we know that √-1=i

Hence,√-a=√ai

we can simplify given expression by using above equation.

18-√-25

18-√-1√25

18-i√25

18-√25i

As 25 is square of 5.

Hence ,

18-5i which is the answer.

enot [183]3 years ago

6 0

Answer:

Option (2) is correct.

$18-\sqrt{-25}=18-5i$

Step-by-step explanation:

Given expression $18-\sqrt{-25}$

We have to find an equivalence value to the expression.

Radical rule,

$\sqrt{-a}=\sqrt{-1} \sqrt{a}$

Also, $i=\sqrt{-1}$

Consider the given expression,

$18-\sqrt{-25}$

Applying radical rule to $\sqrt{-25}$

$\sqrt{-25}=\sqrt{-1}\sqrt{25}=5i$

Thus, the expression becomes,

$18-\sqrt{-25}=18-5i$

Thus, option (2) is correct.

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Find the angle between u = (-2,-5) and v = (5,2)

OleMash [197]

The angle between u = (-2,-5) and v = (5,2) is 134 degrees approximately.

Solution:

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We have to find the angle between two vectors.

We know that,

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$\text { Now vectors are }(-2 \vec{\imath}-5 \vec{\jmath}) \text { and }(5 \vec{\imath}+2 \vec{\jmath})$

$(-2 \vec{\imath}-5 \vec{\jmath}) \cdot(5 \vec{\imath}+2 \vec{\jmath})=\sqrt{(-2)^{2}+(-5)^{2}} \times \sqrt{5^{2}+2^{2}} \times \cos \theta$

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$\begin{array}{l}{-10-10=\sqrt{29} \times \sqrt{29} \times \cos \theta} \\\\ {-20=29 \times \cos \theta} \\\\ {\cos \theta=\frac{-20}{29}} \\\\ {\theta=\cos ^{-1} \frac{-20}{29}} \\\\ {\theta=133.60}\end{array}$

Hence, the angle between given two vectors is 134 degrees approximately.

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3 years ago

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NemiM [27]

Answer:

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Step-by-step explanation:

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e(f +g) = e*f + e*g

= ef + eg

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Step-by-step explanation:

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prohojiy [21]

Explanation:

This can be explained by thinking numbers on the number line as:

Lets take we have to multiply a positive number (say, 2) with a negative number say (-3)

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A image is shown below to represent the same.

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