Answer:
2.
Step-by-step explanation:
For #2, another way to word this question is: For which of the following trig functions is π/2 a solution? Well, go through them one by one. If you plug π/2 into sinθ, you get 1. This means that when x is π/2, y is 1. Try and visualize that. When y is 1, that means you moved off the x-axis; so y = sinθ is NOT one of those functions that cross the x-axis at θ = π/2. Go through the rest of them. For y = cos(π/2), you get 0. At θ = π/2, this function crosses the x-axis. For y = tanθ, your result is undefined, so that doesn't work. Keep going through them. You should see that y = secθ is undefined, y = cscθ returns 1, and y = cotθ returns 0. If you have a calculator that can handle trig functions, just plug π/2 into every one of them and check off the ones that give you zero. Graphically, if the y-value is 0, the function is touching/crossing the x-axis.
Think about what y = secθ really means. It's actually y = 1/(cosθ), right? So what makes a fraction undefined? A fraction is undefined when the denominator is 0 because in mathematics, you can't divide by zero. Calculators give you an error. So the real question here is, when is cosθ = 0? Again, you can use a calculator here, but a unit circle would be more helpful. cosθ = π/2, like we just saw in the previous problem, and it's zero again 180 degrees later at 3π/2. Now read the answer choices.
All multiples of pi? Well, our answer looked like π/2, so you can skip the first two choices and move to the last two. All multiples of π/2? Imagine there's a constant next to π, say Cπ/2 where C is any number. If we put an even number there, 2 will cut that number in half. Imagine C = 4. Then Cπ/2 = 2π. Our two answers were π/2 and 3π/2, so an even multiple won't work for us; we need the odd multiples only. In our answers, π/2 and 3π/2, C = 1 and C = 3. Those are both odd numbers, and that's how you know you only need the "odd multiples of π/2" for question 3.
Answer: {(x + 2), (x - 1), (x - 3)}
Step-by-step explanation:
Presented symbolically, we have:
x^3 - 2x^2 - 5x + 6
Synthetic division is very useful for determining roots of polynomials. Once we have roots, we can easily write the corresponding factors.
Write out possible factors of 6: {±1, ±2, ±3, ±6}
Let's determine whether or not -2 is a root. Set up synthetic division as follows:
-2 / 1 -2 -5 6
-2 8 -6
-----------------------
1 -4 3 0
since the remainder is zero, we know for sure that -2 is a root and (x + 2) is a factor of the given polynomial. The coefficients of the product of the remaining two factors are {1, -4, 3}. This trinomial factors easily into {(x -1), (x - 3)}.
Thus, the three factors of the given polynomial are {(x + 2), (x - 1), (x - 3)}
Answer:
ab
Step-by-step explanation:
When all of the variables are the same in a problem, think of them as the same term. They can be added and subtracted just as you would add and subtract normal numbers.
For example if I have 5 bananas on a table and take away 3 bananas. I only have two bananas left (2b). It's the same when there are variables!
Subtract 9 from 3:
-6ab+7ab
Add -6 to 7:
ab
Your final answer is ab!
Answer:
2x+3
Step-by-step explanation:
Let x be the number
twice a number
2x
3 more than
2x+3
Answer:
at 6pm it was 18 degrees
Step-by-step explanation:
10 pm: -10
9 pm : -3
8 pm: 4
7 pm: 11
6 pm: 18
Add 7
