# Thread: Multiple Choice Help, Derivatives.

1. ## Multiple Choice Help, Derivatives.

The position of a particle moving on the x axis is given by x(t)=t^2-5sin(0.8t). for what value of t is the particle furthest left?

a. -1.77
b. -1.287
c. 1.287
d. 1.177
e. 1.391

I derived the function to get the velocity function and found that -1.77 is the correct answer.

A function has a derivative given by f '(x)= sqrt(x)/x^2+x+1. What is the x cooridnate of the inflection point of f?

a. -0.768
b. 0
c. 0.434
d. 1
e. no inflection point

I graphed it on my graphing calculator and got 0.434.

Can someone tell me if these answers are correct?

2. Originally Posted by Jon911
The position of a particle moving on the x axis is given by x(t)=t^2-5sin(0.8t). for what value of t is the particle furthest left?

a. -1.77
b. -1.287
c. 1.287
d. 1.177
e. 1.391

I derived the function to get the velocity function and found that -1.77 is the correct answer.

incorrect ... the particle is farthest to the left when x(t) is a minimum.

A function has a derivative given by f '(x)= sqrt(x)/x^2+x+1. What is the x cooridnate of the inflection point of f?

a. -0.768
b. 0
c. 0.434
d. 1
e. no inflection point

I graphed it on my graphing calculator and got 0.434.

correct
...

3. How would you go about solving this?

4. Originally Posted by Jon911
How would you go about solving this?
look at the graph of x(t)