Answer:
the answer is c
Step-by-step explanation:
i just took a test with this question on it.
By "which is an identity" they just mean "which trigonometric equation is true?"
What you have to do is take one of these and sort it out to an identity you know is true, or...
*FYI: You can always test identites like this:
Use the short angle of a 3-4-5 triangle, which would have these trig ratios:
sinx = 3/5 cscx = 5/3
cosx = 4/5 secx = 5/4
tanx = 4/3 cotx = 3/4
Then just plug them in and see if it works. If it doesn't, it can't be an identity!
Let's start with c, just because it seems obvious.
The Pythagorean identity states that sin²x + cos²x = 1, so this same statement with a minus is obviously not true.
Next would be d. csc²x + cot²x = 1 is not true because of a similar Pythagorean identity 1 + cot²x = csc²x. (if you need help remembering these identites, do yourslef a favor and search up the Magic Hexagon.)
Next is b. Here we have (cscx + cotx)² = 1. Let's take the square root of each side...cscx + cotx = 1. Now you should be able to see why this can't work as a Pythagorean Identity. There's always that test we can do for verification...5/3 + 3/4 ≠ 1, nor is (5/3 + 3/4)².
By process of elimination, a must be true. You can test w/ our example ratios:
sin²xsec²x+1 = tan²xcsc²x
(3/5)²(5/4)²+1 = (4/5)²(5/3)²
(9/25)(25/16)+1 = (16/25)(25/9)
(225/400)+1 = (400/225)
(9/16)+1 = (16/9)
(81/144)+1 = (256/144)
(81/144)+(144/144) = (256/144)
(256/144) = (256/144)
Answer:
(0, -9) (1, -5)
Step-by-step explanation:
We know from the equation y = 4x -9, that the slope of the line is 4, and the point that the line crosses the y-intercept is at -9. So, your first point would be at (0, -9) and if you go one value over on the x-coordinate, that means the y-coordinate will go 4 up. So your final point will be (1, -5). The point could also be (2, -1), (3, 3), (4, 7), (5, 11), etc.
I Hope That This Helps! :)
Answer:
0.75
Step-by-step explanation:
-6x+2x=6-9
-6x+2x=6-9
-4x=-3
x=-3/-4
x=0.75
Hope this will help ya!
Answer:
see the attached
Step-by-step explanation:
Each digit goes in the place corresponding to its place value.
When no digit has a given place value, a placeholder is used. That is the purpose of zero, a great invention in the history of mathematics. It makes place-value number systems possible.
