Graph

• bonkysleuth

  17 Apr 08, 21:52

  Draw te graph of y = 2x^2 +1 for =3 equal to or less than X, equal to or less than 3.

   

  By drawing a tangent , find the gradient of the curve at the point

  B (2,9)

  The answer's 8 but i got 6.6....

   

  Draw the graph of y = x^3 for -2< or equal to x < or equal 2

  by drawing a tangent, find gradient of curve at the point where x = -1.

   

  the answer's 3 . but i got 4 despite many tries. could someone try drawing this out and see whether the answer scheme is correct??

• purpledragon84

  18 Apr 08, 01:33

  this kind of thing.. u have to see whether ur graph good or not one la..

  ALTERNATIVELY..

  qn1.

  u noe how to do differentiation rite?

  dy/dx = 4x.. sub x = 2 u get 8 lo.. haha..

  qn 2.

  dy/dx = 3x^2.. sub x = -1, u get 3 lo.. haha..

   

  so i can tell u.. if u draw ur graph correctly, u shud get the answer.. so the only problem is ur graph drawing

• secretliker

  19 Apr 08, 01:34

  Make sure your graph is smooth, and tangent only touches one point.