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almond37 [142]
3 years ago
9

Please answer quickly

Mathematics
1 answer:
Aleks04 [339]3 years ago
8 0

Answer:

<em> -√5/5</em>

Step-by-step explanation:

Given the following

sin(A) = 4/5

sinB - -2√5/5

SinA = 4/5 = opp/hyp

We can get cosA

opposite = 4

hypotenuse = 5

Adj = √5²-4² (pythagoras theorem)

Adj = √25-16

Adj = √9

Adj = 3

Cos A = Adj/hyp

Cos A = 3/5

Also

Sin B = -2√5/5 = opp/hyp

opposite = -2√5

hypotenuse = 5

Adj = √5²-(2√5)² (pythagoras theorem)

Adj = √25-20

Adj = √5

Cos B = Adj/hyp

Cos B =  √5/5

Evaluate cos (A-B)

cos (A-B) = cosAcosB + sinAsinB

cos (A-B) = 3/5(√5/5)+4/5(-2√5/5)

cos (A-B)  = 3√5/25 - 8√5/25

cos (A-B) = -5√5/25

cos (A-B) = -√5/5

<em>Hence the value of cos (A-B) is -√5/5</em>

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82.8cm measured to the nearest tenth of a centimetre.
RoseWind [281]

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82.8 cm measured to the nearest tenth of 80cm.

6 0
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You and your friend go bowling your score is 6 more that twice your friends score if your score is 212 what is your friends scor
kotegsom [21]

Answer:

103

Step-by-step explanation:

your friend's score=x

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8 0
2 years ago
Which of the following is not equal to sin⁡(-230°)?
xenn [34]

From trigonometry we know that:

if sin(\theta)=sin(\alpha)

then, \theta=n\pi+(-1)^n\alpha (where n is an integer)

This can be rewritten in degrees as:

\theta=n(180^{\circ})+(-1)^n\alpha.............(Equation 1)

Now, in our case, \alpha=-230^{\circ}

Therefore, (Equation 1) can be written as:

\theta=n(180^{\circ})+(-1)^n(-230^{\circ})..........(Equation 2)

Now, to find the correct options all that we have to do is replace n by relevant integers and find the values of \theta that match.

For n=2, (Equation 2) gives us: \theta=2\times 180^{\circ}+(-1)^2(-230^{\circ})=360^{\circ}-230^{\circ}=130^{\circ}.

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Let n=-1, then:

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Thus, sin(-230^{\circ})=-sin(-50^{\circ})

Likewise, sin(-230^{\circ})=sin(50^{\circ})

Only the last option sin(-50^{\circ}) will never match sin(-230^{\circ}) because no integral value of n will ever give \theta=-50^{\circ}

Thus the last option is the correct option.

3 0
3 years ago
Read 2 more answers
I will say tje question "use the rule to write the first five terms of the pattern rule add 10 subtract 5" can anyone help??
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You're basically adding five because 10 - 5 = 5. Start from zero.

5, 10, 15, 20, 25
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