Answer:

Step-by-step explanation:
You have to find a, b, c, r so that the polynomial expands to match the given equation.








I assume there's a plus sign missing above...
Convert to polar coordinates, using

Then the Jacobian is

Then

so the integral can be written as

Let

, so that

.
I Don’t Know If Still Need The Answer But It Should Be A.
Answer:
90 mi/h
Step-by-step explanation:
Given,
For first 30 miles, her speed is 30 miles per hour,
Let x be her speed in miles per hour for another 30 miles,
Since, here the distance are equal in each interval,
So, the average speed of the entire journey


According to the question,



Hence, she needs to go 90 miles per hour for remaining 30 miles.