Saturday

October 25, 2014

October 25, 2014

Posted by **rob** on Friday, July 22, 2011 at 8:27am.

just give me some hint to calculate this solution.

- math -
**Reiny**, Friday, July 22, 2011 at 8:50amdy/dx = 2x + 5

slope of tangent at (1,4) = 2(1) +5 = 7

at (1,4) ...

4 = 7(1) + b

b= -3

tangent equation at (1,4) is y = 7x - 3

at (-3,-8)

slope of tangent is 2(-3) + 5 = -1

so slope of normal is +1

equation of normal is y = x + b

at (-3,-8) , -8 = -3 + b

b = -5

equation of normal is y = x - 5

where do they intersect ?

when 7x - 3 = x - 5

6x = -2

x = -1/3

back into y = x-5 , (or the other equation, makes no differencen)

y = - 1/3 - 5 = -1/3 - 15/3 = -16/3

so the two straight lines intersect at (-1/3, -16/3)

**Answer this Question**

**Related Questions**

calculus - 1. Given the curve a. Find an expression for the slope of the curve ...

calculus - Consider the curve defined by 2y^3+6X^2(y)- 12x^2 +6y=1 . a. Show ...

Please check my maths? - How should i do this question?? it says: find the ...

math - find the coordinates of the point where the tangent to the curve y=x^3 +x...

math - A curve has implicit equation x^2-2xy+4y^2=12 a)find the expression for ...

calculus - Consider line segments which are tangent to a point on the right half...

calculus - A curve passes through the point (1,-11) and it's gradient at any ...

12th Grade Calculus - 1. a.) Find an equation for the line perpendicular to the ...

calculus - there are two tangents lines to the curve f(x) = 3x^2 that pass ...

Maths - The tangent to the curve 2y= 2x^2 -5x +4 at the point where x=1 is ...