Simple integral: int {-3x + 5} / {x ^ 2-2x + 5} dx =?

Simple integral: int {-3x + 5} / {x ^ 2-2x + 5} dx =?
Anonim

Sagot:

#int (-3x + 5) / (x ^ 2-2x + 5) * dx #

# = arctan ((x-1) / 2) -3 / 2ln (x ^ 2-2x + 5) #

Paliwanag:

#int (-3x + 5) / (x ^ 2-2x + 5) * dx #

=# -int (3x-5) / (x ^ 2-2x + 5) * dx #

=# -int (3x-3-2) / (x ^ 2-2x + 5) * dx #

=# -int (3x-3) / (x ^ 2-2x + 5) * dx #+#int 2 / (x ^ 2-2x + 5) * dx #

=#int 2 / ((x-1) ^ 2 + 4) * dx #-# 3 / 2int (2x-2) / (x ^ 2-2x + 5) #

=#arctan ((x-1) / 2) -3 / 2ln (x ^ 2-2x + 5) #

Sagot:

# = - 3 / 2ln (x ^ 2-2x + 5) + tan ^ -1 ((x-1) / 2) + C #

Paliwanag:

#int (-3x + 5) / (x ^ 2-2x + 5) dx #

# = int (-3x + 5-2 + 2) / (x ^ 2-2x + 5) dx #

# = int (-3x + 3) / (x ^ 2-2x + 5) + 2 / (x ^ 2-2x + 5) dx #

# = - int (3x-3) / (x ^ 2-2x + 5) dx + int2 / (x ^ 2-2x + 5) dx #

Para sa:

# -int (3x-3) / (x ^ 2-2x + 5) dx #

Gamitin ang pagpapalit:

# u = x ^ 2-2x + 5 #

#implies du = 2x-2dx nagpapahiwatig 3 / 2du = 3x-3dx #

#dalawang -int (3x-3) / (x ^ 2-2x + 5) dx = -int (3/2) / udu = -3 / 2ln (u) + C #

Baligtarin ang pagpapalit:

# -3 / 2ln (x ^ 2-2x + 5) + C #

Ngayon para sa iba pang mahalaga:

# int2 / (x ^ 2-2x + 5) dx #

Isulat ang denominator sa nakumpleto na parisukat na form:

# x ^ 2-2x + 5 = (x-1) ^ 2 - (- 1) ^ 2 + 5 = (x-1) ^ 2 + 4 #

Kaya:

# int2 / (x ^ 2-2x + 5) dx = 2intdx / ((x-1) ^ 2 + 4) #

Ngayon kapalit:

# 2u = (x-1) #

#implies du = 2dx # Kaya:

# 2intdx / ((x-1) ^ 2 + 4) = 2int2 / (4u ^ 2 + 4) du = 4 / 4int1 / (u ^ 2 + 1) du #

Ang makilala natin ay isasama lamang sa kabaligtaran na nagbibigay sa atin:

# = tan ^ -1 (u) + C '#

Baligtarin ang pagpapalit:

# = tan ^ -1 ((x-1) / 2) + C '#

Kaya, ang "isang bagay" ay:

#int (-3x + 5) / (x ^ 2-2x + 5) dx #

# = - int (3x-3) / (x ^ 2-2x + 5) dx + int2 / (x ^ 2-2x + 5) dx #

# = - 3 / 2ln (x ^ 2-2x + 5) + tan ^ -1 ((x-1) / 2) + C #