Y>3 is the correct answer because more than 3 inches of rain fell.
Formula for curvature for a well behaved curve y=f(x) is
K(x)= ![\frac{|{y}''|}{[1+{y}'^2]^\frac{3}{2}}](https://tex.z-dn.net/?f=%5Cfrac%7B%7C%7By%7D%27%27%7C%7D%7B%5B1%2B%7By%7D%27%5E2%5D%5E%5Cfrac%7B3%7D%7B2%7D%7D)
The given curve is y=7
k(x)=![\frac{7e^{x}}{[{1+(7e^{x})^2}]^\frac{3}{2}}](https://tex.z-dn.net/?f=%5Cfrac%7B7e%5E%7Bx%7D%7D%7B%5B%7B1%2B%287e%5E%7Bx%7D%29%5E2%7D%5D%5E%5Cfrac%7B3%7D%7B2%7D%7D)
![{k(x)}'=\frac{7(e^x)(1+49e^{2x})(49e^{2x}-\frac{1}{2})}{[1+49e^{2x}]^{3}}](https://tex.z-dn.net/?f=%7Bk%28x%29%7D%27%3D%5Cfrac%7B7%28e%5Ex%29%281%2B49e%5E%7B2x%7D%29%2849e%5E%7B2x%7D-%5Cfrac%7B1%7D%7B2%7D%29%7D%7B%5B1%2B49e%5E%7B2x%7D%5D%5E%7B3%7D%7D)
For Maxima or Minima
→
[not possible ∵there exists no value of x satisfying these equation]
→
Solving this we get
x= 
As you will evaluate 
<0 at x=
So this is the point of Maxima. we get y=7×1/√98=1/√2
(x,y)=[,1/√2]
k(x)=![\lim_{x\to\infty } \frac{7e^{x}}{[{1+(7e^{x})^2}]^\frac{3}{2}}](https://tex.z-dn.net/?f=%5Clim_%7Bx%5Cto%5Cinfty%20%7D%20%5Cfrac%7B7e%5E%7Bx%7D%7D%7B%5B%7B1%2B%287e%5E%7Bx%7D%29%5E2%7D%5D%5E%5Cfrac%7B3%7D%7B2%7D%7D)
k(x)=
k(x)=0
Answer: First half was 24 minutes
Step-by-step explanation:
Let the time taken to finish the second half be y.
Since the student used 2/3 of the second half time to finish the first half, first half = 2/3 × y = 2y/3
The entire exam is an hour which equals 60 minutes
First half + Second half = 60minutes
Note that first half is denoted as 2y/3 and second half is denoted by y.
2y/3 + y = 60
5y/3 = 60
Cross multiply
5y = 60 × 3
5y = 180
y = 180/5
y = 36
Second half took 36 minutes
Since first half is 2y/3, it will be:
(2×36) / 3
= 72/3
= 24minutes
First half took 24 minutes.
