7.1
It is important to note that both the numerator and the denominator tend to 0 so I will use L'Hopital's rule.
\(\displaystyle\lim_{x\rightarrow 2}\;\frac{x^2-x-2}{x^2-3x+2}\\ =\displaystyle\lim_{x\rightarrow 2}\;\frac{\frac{d}{dx}(x^2-x-2)}{\frac{d}{dx}(x^2-3x+2)}\qquad \text{Using L'hopital's Rule }\\ =\displaystyle\lim_{x\rightarrow 2}\;\frac{2x-1}{2x-3}\\ =\frac{3}{1}\\ =3\)
Это лучший способ сделать это.
This is a better way to do it.
\(\displaystyle\lim_{x\rightarrow 2}\;\frac{x^2-x-2}{x^2-3x+2}\\ =\displaystyle\lim_{x\rightarrow 2}\;\frac{(x-2)(x+1)}{(x-2)(x-1)}\\ =\displaystyle\lim_{x\rightarrow 2}\;\frac{(x+1)}{(x-1)}\\ =\frac{3}{1}\\ =3\)
5.1( a ) arcsin [ cos (pi/3) ] - sin [ arcsin (-1/2) ] =
arcsin [ 1/2] - (-1/2)
pi / 6 + 1/2
(b) arctan [cos (pi) ] - arctan [ tan (3pi/ 7) ] =
arctan [ -1] - 3pi/ 7
- pi/ 4 - 3pi / 7
- [ 7 pi + 12 pi ] /28
- 19pi / 28
5.2 ( a) arccos [ cos (pi/5) ] - sin [ arctan (-1) ] =
pi / 5 - sin [ - pi / 4 ]
pi / 5 - [ - 1 / √2]
pi / 5 + [ 1 / √2]
(b ) arctan [ cos (pi/3) ] - tan [ arctan (3pi / 7) ] =
arctan [ 1/2 ] - 3pi / 7
5.3 (a) arccos [ cos (pi / 5) ] - sin [ arctan (-1) ] =
pi / 5 - sin [ - pi / 4 ] =
pi / 5 - [ - 1 / √2 ] =
pi / 5 + [1 / √2 ]
(b) same as 5.2 (b)
lim √ [2 - x ] - 1
x →1 _________
x - 1
lim √ [2 - x ] - 1 √ [2 - x ] + 1
x →1 _________ __________
x - 1 √ [2 - x ] + 1
lim 2 - x - 1
x → 1 __________________
( x - 1) ( √ [2 - x ] + 1)
lim
x → 1 1 - x
___________________
( x - 1) ( √ [2 - x ] + 1)
lim - ( x - 1 )
x → 1 ______________________
( x - 1) ( √ [2 - x ] + 1)
lim -1 -1
x → 1 _________________ = ____
√ [2 - x ] + 1 2
https://www.desmos.com/calculator/ev6xzdsszs
lim sin (x)
x → pi _____
x - pi
Note sin (pi- x) = sin pi cosx - sinx cospi = sin (x) .....so........
lim sin ( pi - x)
x → pi ________
x - pi
1 lim sin ( pi - x)
__ * x → pi __________
-1 ( pi - x )
Note lim sin (pi - x) lim sin (x)
x→ pi _______ = x → 0 _____ = 1
pi - x x
So
lim sin (x)
x → pi _____ = (-1) * (1) = -1
x - pi