Calc help...

[Syntex]

So I got an idiot teacher who can't explain things for shit and I am lost on a few problems and hoping someone can help me out.

Okay 2 problems I am having trouble with...

1) The parabola y=(x^2) + Ax + B has a tangent line at (3,4) and a y-intercept at 1. Find A and B.

I thought you would find the slope of the tangent line(which is 1) then plug it into the derivative and work backwards to find A then fill in the blanks to find B which I did but when I graphed it to check mywork the tangent line is like crossing at like -5 on the y-axis so somethings not right.

2) A ball rolls down an inclined plane such that the distance(in cm) it rolls in t seconds is given by s(t)= (2t^3) + (3t^2) + 4 where 0<t<3.

What is the velocity of the ball at t=2 and at what time is the velocity 30cm/sec?

Kinda confused on the 2nd one

Any help would be appreciated.

[Flarega]

1) y=1 at x=0 so B has to be 1. For the second part, if you're sure the slope at (3,4) is 1, your equation is: 1 = 2x + A where x = 3.

2) Velocity = derivative of position(distance) Take the derivative and put in t=2 into it. To find the time at which v=30cm/s, put that into the eq for velocity.

[Cadsuane]

So I got an idiot teacher who can't explain things for shit and I am lost on a few problems and hoping someone can help me out.

Okay 2 problems I am having trouble with...

1) The parabola y=(x^2) + Ax + B has a tangent line at (3,4) and a y-intercept at 1. Find A and B.

I thought you would find the slope of the tangent line(which is 1) then plug it into the derivative and work backwards to find A then fill in the blanks to find B which I did but when I graphed it to check mywork the tangent line is like crossing at like -5 on the y-axis so somethings not right.

2) A ball rolls down an inclined plane such that the distance(in cm) it rolls in t seconds is given by s(t)= (2t^3) + (3t^2) + 4 where 0<t<3.

What is the velocity of the ball at t=2 and at what time is the velocity 30cm/sec?

Kinda confused on the 2nd one

Any help would be appreciated.

Your solution for 1 sounds correct. Are you just forgetting how to do anti-derivatives?