If cosa = -4/5 with a in QIII. Find sin2a
2 answers:
Since a is in the third quadrant, both sina and cosa are negative.
Now, sin(2a) can be rewritten as 2sin(a)cos(a).
Thus, we can find sin(a) by using Pythagoras' Theorem.
Now, by focusing on the positive value, we can see that 5 is the hypotenuse.
Let the missing side be x.
x² + 16 = 25
x² = 9
x = 3, because x > 0
Substituting these into the equation, we get:
Now, sin(2a) can be rewritten as 2sin(a)cos(a).
Thus, we can find sin(a) by using Pythagoras' Theorem.
Now, by focusing on the positive value, we can see that 5 is the hypotenuse.
Let the missing side be x.
x² + 16 = 25
x² = 9
x = 3, because x > 0
Substituting these into the equation, we get:
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<h2>Answer</h2>
210 pounds
<h2>Explanation </h2>First, we are going to find the exchange rate from dollars to pounds.
We know form our problem that 800 dollars are 560 pounds. so:
pounds per dollar.
Next, we are going to multiply our exchange rate by the number of dollars we want to change, 300:
We will get 210 pounds for 300 dollars