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lina2011 [118]
3 years ago
12

Help me out hereeeeeeeeeeeeeeeeeeee

Mathematics
2 answers:
aalyn [17]3 years ago
8 0

Answer:

12 stamps

Step-by-step explanation:

21 * 3/7 = 9 (to the sister)

21 - 9 = 12 (what he has left)

ValentinkaMS [17]3 years ago
3 0

Answer:

21 DIVIed by 3/7

Step-by-step explanation:

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Write the trigonometric expression sin(sin−1u−tan−1v) as an algebraic expression in u and v. Assume that the variables u and v r
igomit [66]

Answer:

[u – v√(1 – u²)]/√(1 + v²)

Step-by-step explanation:

Let sin^-1(u) = A, therefore sinA = u.

We know that sin(theta) = opposite/hypothenuse

Therefore, sinA = u/1 and u is the opposite side to angle A while 1 is the hypotenuse. Draw an acute triangle placing u opposite to angle A and 1 as the hypotenuse. By Pythagoras theorem the adjacent would be √(1 – u²).

By doing this, it means cosA = adjacent/hypotenuse = √(1 – u²)/1 = √(1 – u²)

Also, let tan^-1(v) = B, therefore tanB = v.

We know that tan(theta) = opposite/adjacent

Therefore, tanB = v/1 and v is the opposite side to angle B while 1 is the adjacent. Draw an acute triangle placing v opposite to angle B and 1 as the adjacent. By Pythagoras theorem the hypothenuse would be √(1 + v²).

Therefore, sinB = opposite/hypotenuse = v/√(1 + v²) and cosB = adjacent/hypotenuse = 1/√(1 + v²)

Now,

sin[sin^–1(u) – tan^–1(v)] =

sin(A – B) =

sinAcosB – sinBcosA =

u[1/√(1 + v²)] – [v/√(1 + v²)][√(1 – u²)] =

[u/√(1 + v²)] – [v√(1 – u²)/√1 + v²)] =

[u – v√(1 – u²)]/√(1 + v²).

8 0
3 years ago
"sam's furniture was destroyed by a fire. the furniture cost $1200 when it was purchased, but similar new furniture now costs $1
oee [108]
Deprecated means the price is decreased, so if something is deprecated by 50% (which just means 1/2 is taken away) its original price is just cut in half. so half of 1200 (1200 divided by 2) is 600. i think the answer is 600 :-)
8 0
3 years ago
Please help i have no clue what to do <br> i suck at math
beks73 [17]
The first one is 63.9 and the second should be 116.1
3 0
3 years ago
An angle is made up of 66 one-degree angles. What is the measure of the angle?
liraira [26]

Answer:

66 degrees

Step-by-step explanation:

if there are 66 one degree angles, all alll those together to get 66 degrees in total

7 0
3 years ago
Read 2 more answers
Sara got 720 marks out of 800 in the Basic Level Examination. How many percent of marks did she obtain?​
RUDIKE [14]
90% is obtained by Sara
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3 years ago
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