Question

If cos x + x sin x = 2,
then x =​

Answer 1

Step-by-step explanation:

cosx=

sinx

=0

cosx=

sinx

Squaring on both sides

cos

2

x=sinx

[∴cos

2

x=1−sin

2

x]

1−sin

2

x=sinx

sin

2

x=sinx

sin

2

x+sinx−1=0

Let sinx=y

y

2

+y−1

2(1)

−1±

(1)

2

−4(1)(−1)

y=

2

−1±

5

sinx



=

2

−1−

5

∣ sinx=

2

−1+

5



=−1.6

since sinx lies between −1 and 1 ∴sinx=

2

5

−1

x=sin

−1

(

2

5

−1

)