A car travels at a constant velocity of 84 km/hr. How far would the car travel in 20 minutes?
1 answer:
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Answer:
Step-by-step explanation:
The identities you need here are:
and
You also need to know that
x = rcosθ and
y = rsinθ
to get this done.
We have
r = 6 sin θ
Let's first multiply both sides by r (you'll always begin these this way; you'll see why in a second):
r² = 6r sin θ
Now let's replace r² with what it's equal to:
x² + y² = 6r sin θ
Now let's replace r sin θ with what it's equal to:
x² + y² = 6y
That looks like the beginnings of a circle. Let's get everything on one side because I have a feeling we will be completing the square on this:
Complete the square on the y-terms by taking half its linear term, squaring it and adding it to both sides.
The y linear term is 6. Half of 6 is 3, and 3 squared is 9, so we add 9 in on both sides:
In the process of completing the square, we created within that set of parenthesis a perfect square binomial:
And there's your circle! Third choice down is the one you want.
Fun, huh?
Step-by-step explanation:
our equation is x²+16x = -44
- x²+16x= -44
- x² is the first term so weill have in the middle 2*x* a number
- x²+2*x*8 = -44
- the third term is 8² wich is 64 so we will add it in both sides
- x²+2*x*8+64 = -44+64
- (x+8)² = 20
Now that we have completed the perfect square let's solve the equation
- (x+8)² = 20
- x+8 =
or x+8= -
- x = -8+
so the first answer is the correct one
64; 8 +/-