some maths work?

Question

Curve equation y= (x^2+5x+4) cos 3x
1.Find dy/dx
2.find the equation of the tangent to the curve where x=0

Answer 1

u.dv/dx + v.du/dx is the way you find deribatives of two terms.
Basically you need to define your terms. Call (x^2+5x+4) "u" and call cos3x "v". Find the derivative of both (du/dx and dv/dx) with respect to x then plug in the equation.

Derivatives give you a slope at a certain location. A tangent is a slope so when you have the formula for the derivative of the y term you have, you can plug zero in and find what the slope or tangent is at 0. You should get 5 for an answer.