Which expression is equivalent to cos(1.4x) − cos(0.6x)?
2 answers:
Answer:
A. -2sin(x)sin(0.4x)
Step-by-step explanation:
At x=0, the given expression evaluates to zero.
For x near zero, the given expression is slightly negative. You know this because cos(1.4x) decreases faster than cos(0.6x), so their difference will be negative.
Of the answer choices, you can eliminate C and D because they are not zero at x=0. You can eliminate choice B, because it is positive for values of x near zero. The only viable choice is A:
-2sin(x)sin(0.4x)
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Of course, a graphing calculator can help you figure this out. See the attachment. The given expression is plotted using a solid red line; the answer choice A is plotted using blue dots.
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Answer:
Step-by-step explanation:
Since we're dividing the polynomial by , we'll be using -1 to start the division.
Before setting the division up, let's list the coefficients of from descending powers and the constant.
The coefficient of is 3
Since we don't see an , the coefficient will be 0.
The coefficient of is 5.
Lastly, the constant, which is the term without the is -1.
Refer to the attached picture before continuing.
After referring to the picture, we now have the coefficients for the quotient.
The coefficient of is 3.
The coefficient of is -3.
The constant is 8.
Lastly, since the last number is not zero, it's the remainder just like regular division. This can be tricky to remember, but -9 is not the actual remainder.
The remainder is actually .
Now putting all the pieces together, we get:
