Prelim maths question (1 Viewer)

[super.muppy]

cud someone tell me how to find wat f( x) is if f(a+3)=a+5
like the how part
btw the answer is f(x)=a+2

 

[lolokay]

Re: maths question

let x=a+3
f(x) = a+ 5
= (a+3)+2
= x+2

 

[Fortify]

Re: maths question

Treat a as x so:

f(x+3) = x + 5

f(x) = x + 5 - 3

f(x) = x + 2?

 

[super.muppy]

Re: maths question

ty everyoneeee :wave::wave::wave:

 

[zazzy1234]

Re: maths question

can someone please answer this question

solve for 0≤x≤2pi in exact form
sin2x =1/√2

thanx

 

[super.muppy]

Re: maths question

then how do u do f(x-1)=x^2 -1

 

[Uncle]

Re: maths question

can someone please answer this question

solve for 0≤x≤2pi in exact form
sin2x =1/√2

thanx

The ratios for sin, cos and tan of 30 (π/6), 45 (π/4), 60 (π/3) and 90 (π/2) being commited to memory helps.

sin (π/4) = 1/√2

Not convinced? Draw a triangle with the hypotenuse of length √2 and the adjacent and opposite sides both of length 1, see that the angles in the triangle add up to 180, the 90 degrees is fixed, so you have two 45 degree or two π/4 radian angles.

Anyway,

sin (2x) = sin (π/4)

2x = π/4

x = π/8

 

[lisarh]

Re: maths question

can someone please answer this question

solve for 0≤x≤2pi in exact form
sin2x =1/√2

thanx

sin2x = 1/√2
2x=sin-1(1/√2)
acute 2x = 45
2x = 45, 180-45, 360+45, 540-45
2x = 45, 135, 405, 495
x = 22.5, 67.5, 202.5, 247.5
x = π/8, 3π/8, 9π/8, 11π/8

 

[kurt.physics]

Re: maths question

then how do u do f(x-1)=x^2 -1

all you have to do is substitute x = x+1 into the function

f(x+1-1) = (x+1)² - 1

.: f(x) = x^2 + 2x