Be sure to include the "=" sign: <span>f(x) = 2^x -7
To find the x-intercepts, set f(x) = 0 and solve for x: 2^x - 7 = 0,
or
2^x = 7
Take the common log of both sides: x log 2 = log 7
log 7
Solve for x: x = --------- = 2.81 (approx)
log 2
</span>
Let c > 0. Then split the integral at t = c to write

By the FTC, the derivative is
![\displaystyle \frac{df}{dx} = \left(\frac1x + \sin\left(\frac1x\right)\right) \frac{d}{dx}\left[\frac1x\right] - (\ln(x) + \sin(\ln(x))) \frac{d}{dx}\left[\ln(x)\right] \\\\ = -\frac1{x^2} \left(\frac1x + \sin\left(\frac1x\right)\right) - \frac1x (\ln(x) + \sin(\ln(x))) \\\\ = -\frac1{x^3} - \frac{\sin\left(\frac1x\right)}{x^2} - \frac{\ln(x)}x - \frac{\sin(\ln(x))}x \\\\ = -\frac{1 + x\sin\left(\frac1x\right) + x^2\ln(x) + x^2 \sin(\ln(x))}{x^3}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20%5Cfrac%7Bdf%7D%7Bdx%7D%20%3D%20%5Cleft%28%5Cfrac1x%20%2B%20%5Csin%5Cleft%28%5Cfrac1x%5Cright%29%5Cright%29%20%5Cfrac%7Bd%7D%7Bdx%7D%5Cleft%5B%5Cfrac1x%5Cright%5D%20-%20%28%5Cln%28x%29%20%2B%20%5Csin%28%5Cln%28x%29%29%29%20%5Cfrac%7Bd%7D%7Bdx%7D%5Cleft%5B%5Cln%28x%29%5Cright%5D%20%5C%5C%5C%5C%20%3D%20-%5Cfrac1%7Bx%5E2%7D%20%5Cleft%28%5Cfrac1x%20%2B%20%5Csin%5Cleft%28%5Cfrac1x%5Cright%29%5Cright%29%20-%20%5Cfrac1x%20%28%5Cln%28x%29%20%2B%20%5Csin%28%5Cln%28x%29%29%29%20%5C%5C%5C%5C%20%3D%20-%5Cfrac1%7Bx%5E3%7D%20-%20%5Cfrac%7B%5Csin%5Cleft%28%5Cfrac1x%5Cright%29%7D%7Bx%5E2%7D%20-%20%5Cfrac%7B%5Cln%28x%29%7Dx%20-%20%5Cfrac%7B%5Csin%28%5Cln%28x%29%29%7Dx%20%5C%5C%5C%5C%20%3D%20-%5Cfrac%7B1%20%2B%20x%5Csin%5Cleft%28%5Cfrac1x%5Cright%29%20%2B%20x%5E2%5Cln%28x%29%20%2B%20x%5E2%20%5Csin%28%5Cln%28x%29%29%7D%7Bx%5E3%7D)
Answer:
0.4 = 40% probability that a toy that Raymond picks out of a box is plush given that it is a dinosaur.
Step-by-step explanation:
Conditional Probability
We use the conditional probability formula to solve this question. It is

In which
P(B|A) is the probability of event B happening, given that A happened.
is the probability of both A and B happening.
P(A) is the probability of A happening.
In this question:
Event A: Dinosaur
Event B: Plush.
The probability that a toy Raymond picks out of a box is a dinosaur is 75%.
This means that 
The probability that a toy Raymond picks out of a box is both plush and a dinosaur is 30%.
This means that 
What is the probability that a toy that Raymond picks out of a box is plush given that it is a dinosaur?

0.4 = 40% probability that a toy that Raymond picks out of a box is plush given that it is a dinosaur.