31. (a) If F(x)=5x/(1+x2), find F′(2) and use it to find an equation of the tangent line to the curve y=5x/(1+x2) at the point (2,2).(b) Illustrate part (a) by graphing the curve and the tangent line on the same screen.
Q. 31. (a) If F(x)=5x/(1+x2), find F′(2) and use it to find an equation of the tangent line to the curve y=5x/(1+x2) at the point (2,2).(b) Illustrate part (a) by graphing the curve and the tangent line on the same screen.
Apply Quotient Rule: To find the derivative F′(x) of the function F(x)=1+x25x, we will use the quotient rule, which states that if you have a function that is the quotient of two functions, v(x)u(x), then its derivative is given by (v(x))2v(x)u′(x)−u(x)v′(x). Let u(x)=5x and v(x)=1+x2. Then u′(x)=5 and v′(x)=2x. F′(x)=(v(x))2(v(x)u′(x)−u(x)v′(x))F′(x)=(1+x2)2((1+x2)(5)−(5x)(2x))F(x)=1+x25x0F(x)=1+x25x1
Calculate Derivative: Now we need to evaluate F′(x) at x=2 to find the slope of the tangent line at the point (2,2).F′(2)=(1+(2)2)25−5(2)2F′(2)=(1+4)25−20F′(2)=25−15F′(2)=5−3
Evaluate at x=2: With the slope of the tangent line at the point (2,2) being −53, we can use the point-slope form of the equation of a line to find the equation of the tangent line. The point-slope form is y−y1=m(x−x1), where m is the slope and (x1,y1) is the point on the line.Using the point (2,2) and the slope −53, we get:y−2=(−53)(x−2)
Use Point-Slope Form: To write the equation of the tangent line in slope-intercept form y=mx+b, we will solve for y. y=5−3(x−2)+2 y=5−3x+56+2 y=5−3x+56+510 y=5−3x+516 This is the equation of the tangent line.
Convert to Slope-Intercept Form: For part (b), graphing the curve and the tangent line would require plotting the function y=1+x25x and the line y=5−3x+516 on the same set of axes. This step is more about using graphing software or graphing by hand, and it's not a mathematical calculation step, so we will not perform it here.
More problems from Find derivatives of inverse trigonometric functions