Question

Oblicz x, zadanie w załaczniku

Answer 1

a)

cos30* = 6  / x

√3 / 2 = 6 / x

x * √3 = 2 * 6

x = 12 / √3

x = 12√3 / 3

x = 4√3  

 

b)

x² + x² = (x + 2)²

2x² = x² + 4x + 4

2x² - x² - 4x - 4 = 0

x² - 4x - 4 = 0

Δ = 16 + 16 = 32

√Δ = √32 = √(16 * 2) = 4√2

x1 = (4 - 4√2) / 2 = 2 - 2√2  < 0

x2 = (4 + 4√2) / 2 = 2 + 2√2

odp. x = 2 + 2√2

 

c)

tg60* = (x + 1) / x

√3 / 1 = (x  +1) / x

x + 1 = x * √3

x - x√3 = -1

x(1 - √3) = -1

x = -1 / (1 - √3)

x = -1(1 + √3) / (1 - √3)(1 + √3)

x = -1(1 + √3) / (1 - 3)

x = -1(1 + √3) / (-2)

x = 1/2(1 + √3)

Answer 2

przekatna kwadratu

d=a√2

wiec

x+2=x√2

x(√2-1)=2

x=2/(√2-1) uwymierniam

x=2·(√2+1)

 

tg60°=√3

 

(x+1)/x=√3

x+1=x√3

1=x(√3-1)

x=1/(√3-1) uwymierniam

x=(√3+1)/2

 

 

cos30°=√3/2

6/x=√3/2

6=x√3/2

x=12/√3

x=4√3

 

moze zainteresuje Cie program do rysowania:

http://l5.pk.edu.pl/~kraus/bryly_3d/mini_plot.php

 

Pozdr

 

Hasn