Recent content by wildcat12

Homework Statement I need to find all the zeros of the function f(x)=cos(x)+3cos(3x) on the interval (-pi, pi) Homework Equations The Attempt at a Solution i have found zeros at -pi, -pi/2, 0. pi/2, and pi. Looking at the graph i can see more zeros but i cannot figure out what...

Awesome. i don't know why i didnt get that

Wait i typed that part wrong. i had derivative of sin(3x) as 3Cos(3x)

So plug those numbers in for x? correct?

Homework Statement find the inflection points of the curve y=ln(x^3-3x+4) correct to six decimal places Homework Equations The Attempt at a Solution my first derivative was (3x^2)-3/(x^3)-3x+4) and my 2nd derivative as (-3x^3)+24x+9/(x^3)-3x+4). i do not know how to set this equal...

Homework Statement Find the maxima and minima of the function f(x)=tan(sinx + sin3x) on the interval (-pi,pi) Homework Equations The Attempt at a Solution I found the derivative as sec^2x (sinx +sin3x) (cosx + cos3x) and when i set it equal to zero i found critical points at...

Homework Statement Find, correct to 6 decimal places, the coordinates of the points on the curve y=x^4 that are closest to the point (0,1) Homework Equations The Attempt at a Solution I am not sure if i am supposed to use Newtons method or not

Homework Statement Find a cubic function g(x)=ax^3 +bx^2 +cx +d that has a local maximum value of 2 at -9, and a local minimum value of -7 at 8. Homework Equations The Attempt at a Solution I thought i would find the derivative and set it equal to zero, but i do not know what to...

Homework Statement Show that the equation (9x^5)-(4x^4)+(8x^3)-4x+1=0 has exactly 3 real roots. Homework Equations The Attempt at a Solution I found a derivative of (45x^4)-(16x^3)+(24x^2)-4. I am not sure how to set this equal to zero