Maths [Radius of curvature; partial diff] Flashcards
derivate angle between radius vector and tangent
do doo
what is the angle between two polar curves
Φ1-Φ2 mod
if tan(Φ1)xtan(Φ2)=-1 then the angle is 90 degrees
tanΦ in terms of radius
r dtheta/dr
what is radius of curvature
y, a change in Ψ represents the bending of the curve C and the ratio dΨ/ds represents
the ratio of bending this rate of bending is called the curvature of the curves denoted by K or kappa
P (ro)= 1/K
Radius of curvature in Cartesian form
P = [1+ (y’)^2]^3/2 whole divided by y’’
if We note that when y’=infinte the
use P = [1+ (dx/dy)^2]^3/2 whole divided by dx/dy
Radius of Curvature in Polar Curve r=f(θ)
P= {r^2+r1^2}^3/2 whole divided by r^2 +2 r1^2 - rr2
Centre of curvature formula
The Centre of Curvature at a point „P‟ of a curvature is the point “C” which lies on the Positive direction of the normal at „P‟ and is at a distance (in magnitude) from it.
(X,Y)= ( x- y’(1+y’^2)/y’’ , y +(1+y’^2)/y’’)
Circle of curvature
The circle of curvature at a point „P‟ of a curve is the circle whose centre is at the centre of Curvature C and whose radius is in magnitude.
Taylor’s Mean Value Theorem and formula
Suppose a function satisfies the following two conditions:
(i) and it’s first (n-1) derivatives are continuous in a closed interval [a,b]
(ii) is differentiable in the open interval (a,b)
Then there exists at least one point c in the open interval such that
f(x)= f(a)+(x-a)f’(a)+(x-a)^2f’‘(a)/2!+(x-a)^3f’’‘(a)/3! + (x-a)^4f’’’‘(a)/4! +……….
Maclaurin’s series
f(x)= f(0) + xf’(0)+ x^2 f’‘(0)/2! + x^3 f’’‘(0)/3!