Please show work on these questions!!!

Find the radian measure of an angle of -280 degrees.

Find the degree measure of an angle of 3pi/5 radians.

Find the exact values of cos(3pi/4 radians) and sin(3pi/4 radians).

Respuesta :

Answer:

- 14π/9; 108°; -√2/2; √2/2

Step-by-step explanation:

To convert from degrees to radians, use the unit multiplier [tex]\frac{\pi }{180}[/tex]

In equation form that will look like this:

- 280° × [tex]\frac{\pi }{180}[/tex]

Cross canceling out the degrees gives you only radians left, and simplifying the fraction to its simplest form we have [tex]-\frac{14\pi }{9}[/tex]

The second question uses the same unit multiplier, but this time the degrees are in the numerator since we want to cancel out the radians.  That equation looks like this:

[tex]\frac{3\pi }{5}[/tex] × [tex]\frac{180}{\pi }[/tex]

Simplifying all of that and canceling out the radians gives you 108°.

The third one requires the reference angle of [tex]\frac{3\pi }{4}[/tex].

If you use the same method as above, we find that that angle in degrees is 135°.  That angle is in QII and has a reference angle of 45 degrees.  The Pythagorean triple for a 45-45-90 is (1, 1, √2).  But the first "1" there is negative because x is negative in QII.  So the cosine of this angle, side adjacent over hypotenuse, is [tex]-\frac{1}{\sqrt{2} }[/tex]

which rationalizes to [tex]-\frac{\sqrt{2} }{2}[/tex]

The sin of that angle is the side opposite the reference angle, 1, over the hypotenuse of the square root of 2 is, rationalized, [tex]\frac{\sqrt{2} }{2}[/tex]

And you're done!!!