What is the equation of the line tangent to # f(x)=3/x^2# at # x=-2 #?

1 Answer
Apr 11, 2017

#y=3/4x+9/4#

Explanation:

The equation of the tangent in #color(blue)"point-slope form"# is.

#• y-y_1=m_("tangent")(x-x_1)#

We require #m_("tangent")=f'(-2)" and " (x_1,y_1)#

#f(x)=3/x^2=3x^-2#

#rArrf'(x)=-6x^-3=-6/x^3#

#rArrf'(-2)=(-6)/(-8)=3/4#

#"and "f(-2)=3/(-2)^2=3/4#

#"Using " m=3/4" and " (x_1,y_1)=(-2,3/4)#

#y-3/4=3/4(x+2)#

#rArry=3/4x+9/4larr"is equation of tangent"#