Recall that to get the x-intercepts, we set the f(x) = y = 0, thus
![\bf \stackrel{f(x)}{0}=-4cos\left(x-\frac{\pi }{2} \right)\implies 0=cos\left(x-\frac{\pi }{2} \right) \\\\\\ cos^{-1}(0)=cos^{-1}\left[ cos\left(x-\frac{\pi }{2} \right) \right]\implies cos^{-1}(0)=x-\cfrac{\pi }{2} \\\\\\ x-\cfrac{\pi }{2}= \begin{cases} \frac{\pi }{2}\\\\ \frac{3\pi }{2} \end{cases}](https://tex.z-dn.net/?f=%5Cbf%20%5Cstackrel%7Bf%28x%29%7D%7B0%7D%3D-4cos%5Cleft%28x-%5Cfrac%7B%5Cpi%20%7D%7B2%7D%20%20%5Cright%29%5Cimplies%200%3Dcos%5Cleft%28x-%5Cfrac%7B%5Cpi%20%7D%7B2%7D%20%20%5Cright%29%0A%5C%5C%5C%5C%5C%5C%0Acos%5E%7B-1%7D%280%29%3Dcos%5E%7B-1%7D%5Cleft%5B%20cos%5Cleft%28x-%5Cfrac%7B%5Cpi%20%7D%7B2%7D%20%20%5Cright%29%20%5Cright%5D%5Cimplies%20cos%5E%7B-1%7D%280%29%3Dx-%5Ccfrac%7B%5Cpi%20%7D%7B2%7D%0A%5C%5C%5C%5C%5C%5C%0Ax-%5Ccfrac%7B%5Cpi%20%7D%7B2%7D%3D%0A%5Cbegin%7Bcases%7D%0A%5Cfrac%7B%5Cpi%20%7D%7B2%7D%5C%5C%5C%5C%0A%5Cfrac%7B3%5Cpi%20%7D%7B2%7D%0A%5Cend%7Bcases%7D)
Answer:
See explanation
Step-by-step explanation:
The selling price is $495.
The first washing machine:
- is marked down by 30%
$495 - 100%
$x - 100% - 30% = 70%
Find the value of x:
The second washing machine:
- is marked down by 20% with an additional 10% off
$495 - 100%
$y - 100% - 20% = 80%
Find y:
Now,
$396 - 100%
$z - 100% - 10% = 90%
Find z:
Thus, the sale price of the first washing machine is $347 and the sale price of the second washing machine is $356. The second machine is more expensive.
Answer:
C. x > -7 and x <= 3
Step-by-step explanation:
-3 < x + 4 <= 7
Subtract 4 from the three expressions.
-7 < x <= 3
-7 < x means x > -7.
Then you have x <= 3.
Answer: C. x > -7 and x <= 3
Answer:
(6, -2)
Step-by-step explanation:
The midpoint of the segment RS is point M (5, 3). Therefore, the average of the x coordinates of R and S is 5, and the average of the y coordinates of R and S is 3. The x coordinate of R is 4. For 4 and the x coordinate of S to have an average of 5, the x coordinate of S must be 6. Therefore, our point is of the form (6, y). For 8 and the y coordinate of S to have an average of 3, the y coordinate of S must be -2. Therefore, our answer is (6, -2)
