Answer:
1
+
sec
2
(
x
)
sin
2
(
x
)
=
sec
2
(
x
)
Start on the left side.
1
+
sec
2
(
x
)
sin
2
(
x
)
Convert to sines and cosines.
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1
+
1
cos
2
(
x
)
sin
2
(
x
)
Write
sin
2
(
x
)
as a fraction with denominator
1
.
1
+
1
cos
2
(
x
)
⋅
sin
2
(
x
)
1
Combine.
1
+
1
sin
2
(
x
)
cos
2
(
x
)
⋅
1
Multiply
sin
(
x
)
2
by
1
.
1
+
sin
2
(
x
)
cos
2
(
x
)
⋅
1
Multiply
cos
(
x
)
2
by
1
.
1
+
sin
2
(
x
)
cos
2
(
x
)
Apply Pythagorean identity in reverse.
1
+
1
−
cos
2
(
x
)
cos
2
(
x
)
Simplify.
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1
cos
2
(
x
)
Now consider the right side of the equation.
sec
2
(
x
)
Convert to sines and cosines.
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1
2
cos
2
(
x
)
One to any power is one.
1
cos
2
(
x
)
Because the two sides have been shown to be equivalent, the equation is an identity.
1
+
sec
2
(
x
)
sin
2
(
x
)
=
sec
2
(
x
)
is an identity
Step-by-step explanation:
Answer:
A
Step-by-step explanation:
Answer:
Total number of chairs in the restaurant = 160.
Step-by-step explanation:
Total number of tables in the restaurant = 50
It is given that 40% of the tables have 2 chairs at each table.
40% of 50 = 
= 20
So, 20 tables have 2 chairs at each table.
Number of chairs required for 20 tables = 20 × 2 = 40
Remaining 60% of the tables have 4 chairs at each table.
60% of 50 = 
= 30
So, 30 tables have 4 chairs at each table.
Number of chairs required for 30 tables = 30 × 4 = 120
Hence, total number of chairs in the restaurant = 40 + 120 = 160.
Both answers are not the same. You are correct and your friend is wrong. The situation your teacher gave could have only one other interpretation that would be acceptable and that would be 8t+3 because it is the same number just in a different order.
First, make up some variables to represent the number of Girls and Boys in the choir.
B = number of boys
G = number of girls
You know that there are 4 times as many girls in the choir as boys. Therefore, the equation you can write is:

If you cross-multiply, then you get the simplified equation:
G = 4B
Intuitively this makes sense since if you multiplied the number of boys in the class by 4, that would be equal to the number of girls you have.
Now, we know that the total class size is 60. So girls plus boys equals 60:
G+B = 60
To solve the equation, replace the G in this equation with the replacement you found before, 4B.
G + B = 60 -->
4B + B = 60 -->
5B = 60 -->
B = 12
However, you are trying to find the number of girls, so plug the answer back into your equation.
G + B = 60 -->
G + 12 = 60 -->
G + 12 -12 = 60 - 12 -->
G = 48
The number of girls you have is 48.