The statement The square of any rational number is rational can be rewritten formally as For all rational numbers x, x2 is rational or as For all x, ifx is rational then x2 is rational. Rewrite each of the following statements in the two forms x, and x, if , then or in the two forms x and y, and x and y, if , then .a. The reciprocal of any nonzero fraction is a fraction. b. The derivative of any polynomial function is a polynomial function. c. The sum of the angles of any triangle is 180. d. The negative of any irrational number is irrational. e. The sum of any two even integers is even. f. The product of any two fractions is a fraction.
Chain Rule We need to find derivatives of compositions of 2 or more functions. Ex. f(x) = sin(x^2), g(x)= x + 1, h(x)= cos(sintan(x)) The chain rule F(x)=f(g(x)), F’(x)=f’(g(x))*g’(x) Ex. F(x) = sin(x^2) the other function f(g(x)) is sin(g(x)) the inner function g(x) is x^2 F’(x) = cos(x^2)*d/dx x^2,cos(x^2)*2x Ex. g(x) = x + 1, d/dx( x + 1) = d/dx (x^2+1)^½ The outer function is the power of ½, the inner function is x^2 +1 d/dx [ x^2 +1)^½] = ½(x^2+1)^-½* d/dx(x^2+1) = ½(X^2+1)^-½*2x this answer is perfectly acceptable Ex. d/dx [(x^4+x)^10] = 10(x^4+x)^9 * 4x^3 +1 Ex. d/dx (sin^8(x)) Remember sin^n(x) = (sin(x))^n So d/dx [(sin(x))^8] =8(sin(x))^7 * cos(x) Mini Formula = d/dx ((f(x)^n) = n/f(x))^n-1 * f’(x) Advice always rewrite trig functions like the equation above
