Question

solve these questions

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Answer 1

3). 13 - 4cos²x = 12sinx

9 + 4sin²x = 12sinx

4sin²x - 12sinx + 9 = 0

(2sinx - 3)² = 0

sinx = 3/2 , sinx = 3/2

x = sin⁻¹(3/2)

the general solution for sinx is nπ + (-1)ⁿx

= nπ + (-1)ⁿsin⁻¹(3/2)

HENCE, option (A) is correct,


4) . Min.(1 + sin^4(x)) = 1
Max.(cos^5(x))= 1 :

This possible, when
1 + sin^4(x) = 1 = cos^5(x)
=> sin^4(x) = 0 and cos^5(x) = 1
=> sin(x)= 0 and cos (x) = 1
=> x = nπ and x =2nπ where n is integer.
=> Take intersection of both, we get
x =2nπ where n is integer.
x = 2nπ(n ∈ 1)

HENCE, OPTION (B) IS CORRECT