1.

Write the number of solutions of the equation 4 sin x – 3 cos x = 7.

Answer»

4sin x – 3cos x = 7 

4sin x – 7 = 3cos x 

Squaring both sides 

16(sin x)2 + 49 – 56sin x = 9(cos x)2 

16(sin x)2 + 49 – 56sin x = 9((sin x)2-1) 

16(sin x)- 9(sin x)- 56sin x + 49 + 9 = 0 

7(sin x)- 56sin x + 58 = 0 

Solving the quadratic equation 

Sin x = 6.7774 or 1.2225 

But we know that sinθ lies between [-1,1] 

So there are no solutions for this given equation



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