Recent content by physphys

yes that's what I meant, $$\frac{cos(h)-1}{h},$$ I know that it is in fact the derivative of sinx but when I input the values it tells me in the calculator I'm not getting the same.

I think it's cos(h-1) the question has it written the way I wrote it. H is the same as ΔX because it is a limit. Okay, but is my assumption that the value should be equivalent to sin correct?

Homework Statement Use a calculator to evaluate the quantity (cosh-1) / h for h = 0.1, 0.01, 0.001, and 0.0001. Estimate the value of the limit of h -> 0 of (cos h -1) / h Homework Equations The Attempt at a Solution okay so at 0.1 it is 1.523 x 10^-5 and it goes on like that...

Unredeemed, can you please show me how to go on with the process you are talking about? We were taught to find the distance formula then differentiate and solve when it is 0. I've never studies Lagrange's multipliers.

I don't understand what you mean. We were just taught to use the distance formula D^2 = (X2-X1)^2 + (Y2-Y1)2 I subbed in -2 as x1 and 4 as y1 then the equation of x= y^2 -8y + 18 as X2. Am I doing it wrong?

Homework Statement Find the point(s) on the parabola x= y^2-8y+18 closest to (-2,4) Homework Equations The Attempt at a Solution Using the distance formula I found that d^2 = y^4 - 16y^3 + 105y^2 - 328y + 416 after differentiating I have 2d' = 4y^3 - 48y^2 + 210y -328 I'm not...

Okay so I simplified that farther to achieve this, 2(3x-5) / x-2 > 0. So now how do I i know if X> 5/3 OR X<5/3, also wouldn't there be an inequality in the denominator, such as x>2 or x<2 . Also how do display the mathematical operation like that on the forum?

Homework Statement lx/(x-2)l < 5 Homework Equations The Attempt at a Solution x/(x-2) < 5 x< 5x-10 10 < 4x 5/2 < x x/(x-2) > -5 x > -5x+10 6x > 10 x > 5/3 The answer is x < 5/3 and x > 5/2 so where did I go wrong on the second one?

But the calculator disagrees with the fact that x = -5 is one of them, and also how can I find the other point?

I got a ti84, and i can draw a tangent line and it'll tell me the formula, so when I drew a tangent line through -5, the line was not horizontal completely. If you plug in -5 into 2x^2 + 10x= 0, it works out, but when you plug it back into the first one you don't get 0.

Homework Statement At what points on the curve y = (x^2)/(2x+5) is the tangent line horizontal? Homework Equations Quotient rule The Attempt at a Solution I figured out the derivative which is 2x(2x+5) - 2x^2 ----------------- (2x+5)^2 I also know that for the equation of...

yeah you're right, I got the answer! I just copied the question down wrong. Thanks for the help everyone!

Well we never learned l'hopital's rule yet but after googling it and attempting it i got (1/2) - 1 ---------- (3/2) - (1/2) which gave me -1/4, not the answer. Now as for jbunnii's plan. I got up to - x ( (√3x+1) + (√2x+4) ) ------------------------ (x-3) ((√x+1) + (√2x+1)) I'm unsure...

Homework Statement Evaluate lim x →0 √(x+1) - √(2x+1) ----------------- √(3x+4) - √(2x+4) Homework Equations The Attempt at a Solution First I rationalized the numerator by multiplying everything by √(x+1) + √(2x+1) / √(x+1)...

Wouldn't any acid or base in water reaction be called dissociation?