# Tutor profile: Danny C.

## Questions

### Subject: Pre-Calculus

What is the domain of the function $$f(x) = 1/sqrt(x^2-49)$$?

By examining the function, we can observe that the domain would be [7,inf)

### Subject: Calculus

An objects position can be me modeled by the function $$s(t) = 3t^3-4t^2-8t$$. At what point in time will there be zero net force acting on the object?

There is zero net force acting on an object when the acceleration is zero. To obtain the formula for acceleration we take the second derivative of the position function to get $$a(t) = 18t-8$$. Setting that equal to zero, we get $$a = 8/18$$ or ~0.444

### Subject: Algebra

Find where $$y = 0$$ for the function $$f(x) = 3x^2+8x-6$$

By inspecting the function, we can see that it is quadratic function. Therefor we can use the quadratic formula to find the root. The quadratic formula being $$x = -b±sqrt((b²-4ac)))/(2a)$$, when we plug in values (a = 3, b = 8 c = -6) we get x = 0.610317 and x = −3.27698

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