The first thing I did was substitute the variables in for x and y. This is the numbers in the answer choices: (x,y). I don't know if there is an easier way to do this, but you can replace the two numbers in for the variables since it's multiple choice.

For example,

A: -2+2*4=6 Isn't right

B: 1+2*-1= -1 Nope

C: (0,0) you can already tell it's not right because anything multiplied by 0 is 0.

D: -4+2*1=-2 This is the correct answer.

3 0

3 years ago

Verify:<br>cos(2A)=(cotA-tanA)/cscAsecA

kolbaska11 [484]

Answer:

see explanation

Step-by-step explanation:

Using the trigonometric identities

cot A = $\frac{cosA}{sinA}$ , tanA = $\frac{sinA}{cosA}$ , cscA = $\frac{1}{sinA}$ , secA = $\frac{1}{cosA}$

Consider the right side

$\frac{cotA-tanA}{cscAsecA}$

= $\frac{\frac{cosA}{sinA}-\frac{sinA}{cosA} }{\frac{1}{sinA}.\frac{1}{cosA} }$

= $\frac{\frac{cos^2A-sin^2A}{sinAcosA} }{\frac{1}{sinAcosA} }$

= $\frac{cos^2A-sin^2A}{sinAcosA}$ × sinAcosA ( cancel sinAcosA )

= cos²A - sin²A

= cos2A

= left side ⇒ verified

5 0

3 years ago

Greatest common factor. Can someone please explain

fiasKO [112]

Let's say you have 10 and 15

You can divide both of them by 5

10/5=2
15/5=3

The greatest common factor is 5, because it is the highest number you can divide both numbers by, I hope this helps

3 0

3 years ago