TO SOLVE PROBLEM INVOLVING FUNCTION

Given  f : x → x² – 4x -1, find 

a) the image of 2

f : x → x² – 4x -1
f(x) = x² – 4x -1

when x = 2 

f(2)  = 2² – 4(2) -1

        = 4 – 8 – 1

        = -5

Hence, the image of 2 is -5

// note 

persoalan sekarang is dia nak image of 2, maksudnya object dia adalah 2. 

object tu yang mana? ok 

now function ni dia ada object and image. Image is like hasil dia tau.. F(X) = IMAGE

where the x is the OBJECT.

skang nie dia dah bagi korang OBJECT, tinggal nak carik IMAGE je. as easy as substitution. Masukkanje dalam tu.. masuk masuk masuk, pastu kire kire kire, dapat la jawapan dia.

OBJECT can be any symbol ye.. jgn ingat x je boleh jadi OBJECT. klu aku letak F(s) ; hence the OBJECT will be 's'.

we try other 'twist' okay? 

end note //

b)the object that have the image of 4

// ok, skang klu soalan dia nak dapatkan OBJECT,  yg image dia ialah 4. 

maksud dia pa? f(x) = 4 //

when f(x) = 4,

x² – 4x – 1 = 4     // amik balik dri soalan tu masukkan semula f(x) tu.. pastu ganti2 je//

x² – 4x -5 = 0      // pastu pindah sana sini ( ini bahasa mudah yer bukan terms dia)  //

(x – 1)(x – 5) = 0      // bende nie mudah pakai calculator //

x = -1 or 5

Hence, the objects that have the image of 4 are -1 or 5.

// bende nie mudah je nie.. pasal calculator tu pon ramai mungkin dah tahu.. but just a refresh je la. utk calculator tu buat tuk next post la aku tunjuk cmne.. //