Home
Class 12
MATHS
If int (3sinx+2cosx)/ (3cosx+2sinx) dx=a...

If `int (3sinx+2cosx)/ (3cosx+2sinx) dx=a x+b ln|2sinx+3cosx|+C`, then (a)`a=-(12)/(13),b=(15)/(39)` (b) `a=-7/(13),b=6/(13)` (c)`a=(12)/(13),b=(15)/(39)` (d) `a=-7/(13),b=-6/(13)`

Text Solution

Verified by Experts

We have `I=int(3sinx+2cosx)/(3cosx+2sinx)dx`
Let `3sinx+2cosx=mu(d)/(dx)(3cosx+2sinx)+lambda(3cosx+2sinx)`
`=mu(-3sinx+2cosx)+lambda(3cosx+2sinx)`
Comparing the coefficients of `sin x` and `cosx` on both sides, we get
`-3mu+2lambda=3 " and " 2mu+3lambda=2`
` " or " lambda=(12)/(13) " and " mu=-(5)/(13) `
`:. I=int(mu(-3sinx+2cosx)+lambda(3cosx+2sinx))/(3cosx+2sinx)dx`
`=lambda int 1dx+mu int(-3sinx+2cosx)/(3cosx+2sinx)dx`
`=lambda x +mu int(dt)/(t), " where " t=3cosx+2sinx`
`=lambda x +mu log|t|+C`
`=(12)/(13)x+(-5)/(13)log|3cosx+2sinx|+C`
Promotional Banner

Topper's Solved these Questions

  • INDEFINITE INTEGRATION

    CENGAGE PUBLICATION|Exercise EXAMPLE|18 Videos
  • INDEFINITE INTEGRATION

    CENGAGE PUBLICATION|Exercise CONCEPT APPLICATION EXERCISE 7.1|9 Videos
  • HYPERBOLA

    CENGAGE PUBLICATION|Exercise COMPREHENSION TYPE|2 Videos
  • INEQUALITIES AND MODULUS

    CENGAGE PUBLICATION|Exercise Single correct Answer|21 Videos

Similar Questions

Explore conceptually related problems

Evaluate: int((3sinx-2)cosx)/(5-cos^2x-4sinx)dx

Evaluate: int (2sinx+3cosx)/(3sinx+4cosx )dx

Evaluate : int (2cosx + 3sinx)/(3cosx + 2sin x) dx

If int(sinx)/(sin(x-(pi)/(4)))dx=Af(x)+(1)/(sqrt2)log[|sinx-cosx|]+c, then

If int(sinx^8-cosx^8)/(1-2sinx^2cosx^2)dx= asin2x +c , then find the value of a.

If int sqrtcotx/(sinx cosx) dx = Asqrtcotx + B then A =

If int (sin 2x)/((a+b cosx)^(2))dx=alpha[log_(e )|a+b cos x|+(a)/(a+b cosx)]+c , then alpha=

Evaluate: int(cosx-sinx)/(cosx+sinx)(2+2sin2x)dx

Evaluate int((sinx+cosx)dx)/(sqrt(3+sin2x)).

3(sinx-cosx)^4+6(sinx+cosx)^2+4(sin^6x+cos^6x) is equal to