CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon


Question

If the slope of the tangent to the curve $$y=a{ x }^{ 3 }+bx+4$$ at $$(2,14) = 21$$, then the values of $$a$$ and $$b$$ are respectively


A
2,3
loader
B
3,2
loader
C
3,2
loader
D
2,3
loader

Solution

The correct option is D $$2,-3$$
$$(2,14)$$ lies on the curve $$y=ax^3+bx+4$$
=> $$8a+2b+4=14$$
=> $$4a+b=5$$----(1)

$$\dfrac{dy}{dx}=3ax^2+b|_{x=2}=21$$
=> $$12a+b=21$$--(2)

Solving equations (1) and (2), we get $$a=2, b=-3$$

Mathematics

Suggest Corrections
thumbs-up
 
0


similar_icon
Similar questions
View More


similar_icon
People also searched for
View More



footer-image