Throughout all of these steps I'm only going to alter the left hand side (LHS). I am NOT going to change the right hand side (RHS) at all.
Before I change the LHS of the original equation, let's focus on the given identity
cot^2(x) + 1 = csc^2(x)
Since we know it's an identity, we can subtract 1 from both sides and the identity would still hold true
cot^2(x) + 1 = csc^2(x)
cot^2(x) + 1-1 = csc^2(x)-1
cot^2(x) + 0 = csc^2(x)-1
cot^2(x) = csc^2(x)-1
So we'll use the identity cot^2(x) = csc^2(x)-1
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Now onto the main equation given
cot^2(x) + csc^2(x) = 2csc^2(x) - 1
cot^2(x) + csc^2(x) = 2csc^2(x) - 1 .... note the term in bold
csc^2(x)-1 + csc^2(x) = 2csc^2(x) - 1 .... note the terms in bold
[ csc^2(x) + csc^2(x) ] - 1 = 2csc^2(x) - 1
[ 2csc^2(x) ] - 1 = 2csc^2(x) - 1
2csc^2(x) - 1 = 2csc^2(x) - 1
The bold terms indicate how the replacements occur.
So the original equation has been proven to be an identity because the LHS has been altered to transform into the RHS
Answer: I think 9
Step-by-step explanation:
Answer:
x = 9
Step-by-step explanation:
This shape is a 30-60-90 triangle, which means that the angles of the triangle are each 30°, 60° and 90°. Given that the measures of the angles of the triangle are known, as well as one side, we can find the measures of all the other sides (example attached). A 30-60-90 triangle is special because of the relationship of its sides. The hypotenuse (directly across from the 90° angle) is equal to twice the length (2x) of the shorter leg, in this case labeled 'x' and directly across from the 30° angle. The longer leg, across from the 60° angle, is equal to multiplying the shorter leg (x) by √3 or x√3.
Since the measure of the hypotenuse is given at 18, we can set the expression of that side equal to 18 and solve for x:
2x = 18 or x = 9
65.85 rounded to the nearest tenth is 65.9 because the 5 in the hundredths place is large enough to round the 8 to a 9.