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3 years ago

Please help!!! Trigonometry is so complicated to me

Mathematics

1 answer:

Eva8 [605]3 years ago

3 0

Answer:

x = 4

Step-by-step explanation:

Given that sin(13x) = cos(9x+2)

Since sintheta = cos(90 - theta)

hence sin (13x) = cos (90 -13x)

Substitute into the original equation

cos (90 -13x) = cos(9x+2)

90-13x = 9x+2

-13x - 9x = 2 - 90

-22x = -88

x = 88/22

x = 4

Hence the value of x is 4

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164 is 55% of what number?<br><br> Please somebody help me

monitta

This is how you solve it; but first of all convert the percent into a decimal;55%= 0.55

0.55x = 164 (divide by 0.55 on both sides)
x = 164/0.55
x = 298.18 (rounded to the nearest hundredth)
so 164 is 55% of 298.18(rounded)

8 0

3 years ago

How does place value help you add decimal

gladu [14]

You line up the decimal points so that similar place values are lined up. it will be easier to add them.

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3 years ago

Read 2 more answers

Can somebody please help me with question b please?

snow_tiger [21]

$\bf A=
\begin{bmatrix}
-2&0\\1&3
\end{bmatrix}\qquad B=
\begin{bmatrix}
1&0&3\\-1&3&0
\end{bmatrix}\\\\
-----------------------------\\\\
AB=
\begin{bmatrix}
(-2\cdot 1)+(0\cdot -1)&(-2\cdot 0)+(0\cdot 3)&(-2\cdot 3)+(0\cdot 0)\\\\
(1\cdot 1)+(3\cdot -1)&(1\cdot 0)+(3\cdot 3)&(1\cdot 3)+(3\cdot 0)
\end{bmatrix}$

as you notice above, is the first-row components from A, multiplying all the columns subsequently on B, and you add the products of that row, that gives you one component on the AB matrix

in the one above, we end up with a 2x3 AB matrix

4 0

3 years ago

The National Cancer Institute estimates that 3.65% of women in their 60s get breast cancer. A mammogram can typically identify c

masha68 [24]

Answer:

39.17% probability that a woman in her 60s who has a positive test actually has breast cancer

Step-by-step explanation:

Bayes Theorem:

Two events, A and B.

$P(B|A) = \frac{P(B)*P(A|B)}{P(A)}$

In which P(B|A) is the probability of B happening when A has happened and P(A|B) is the probability of A happening when B has happened.

In this question:

Event A: Positive test.

Event B: Having breast cancer.

3.65% of women in their 60s get breast cancer

This means that $P(B) = 0.0365$

A mammogram can typically identify correctly 85% of cancer cases

This means that $P(A|B) = 0.85$

Probability of a positive test.

85% of 3.65% and 100-95 = 5% of 100-3.65 = 96.35%. So

$P(A) = 0.85*0.0365 + 0.05*0.9635 = 0.0792$

What is the probability that a woman in her 60s who has a positive test actually has breast cancer?

$P(B|A) = \frac{0.0365*0.85}{0.0792} = 0.3917$

39.17% probability that a woman in her 60s who has a positive test actually has breast cancer

7 0

3 years ago

What is the interval notation for the compound inequality? x is less than or equal to -4 or x is greater than or equal to 5?

Tems11 [23]

x is less than or equal to -4 or x is greater than or equal to 5

x <= -4 or x>= 5

There is no intersection of both inequalities when we graph it in number line So, we write the interval notation separately for each inequality

for x<=-4 , x starts at -4 and goes to -infinity because we have less than symbol. Also we have = sign so we use square brackets

Interval notation is (-∞ , -4]

for x>= 5 , x starts at 5 and goes to infinity because we have greater than symbol. Also we have = sign so we use square bracket at 5

Interval notation is [5 , ∞)

Now combine both notation by a 'U' symbol Union

(-∞ , -4] U [5 , ∞)

5 0

3 years ago