Question

If A = 30°, then 3 sin A - 4 sin³ A =
​

Answer 1

Answer:

1

Step-by-step explanation:

3 sin A - 4 sin^3 A

3 sin 30 - 4 sin^3 30 [sin 30° = 1/2]

3 × 1/2 - 4 (1/2) ^3

3/2 - 1/2 = 1

Answer 2

Given :

A = 30°

To find :

3 sin A - 4 sin³ A

Solution :

➝ 3 sin A - 4 sin³ A

put A = 30°

➝ 3 sin 30° - 4 sin³ 30°

We know that :- Sin 30° = 1/2

➝ (3 × 1/2)- 4 (1/2)³

➝ (3/2)- 4 (1/8)

➝ (3/2)- (1/2)

➝ (3-1)/2

➝ 2/2

➝ 1

Answer :

=> 1

Additional Information :

$\begin{array}{ |c |c|c|c|c|c|} \bf\angle A & \bf{0}^{ \circ} & \bf{30}^{ \circ} & \bf{45}^{ \circ} & \bf{60}^{ \circ} & \bf{90}^{ \circ} \\ \\ \rm sin A & 0 & \dfrac{1}{2}& \dfrac{1}{ \sqrt{2} } & \dfrac{ \sqrt{3} }{2} &1 \\ \\ \rm cos \: A & 1 & \dfrac{ \sqrt{3} }{2}& \dfrac{1}{ \sqrt{2} } & \dfrac{1}{2} &0 \\ \\ \rm tan A & 0 & \dfrac{1}{ \sqrt{3} }& 1 & \sqrt{3} & \rm Not \: De fined \\ \\ \rm cosec A & \rm Not \: De fined & 2& \sqrt{2} & \dfrac{2}{ \sqrt{3} } &1 \\ \\ \rm sec A & 1 & \dfrac{2}{ \sqrt{3} }& \sqrt{2} & 2 & \rm Not \: De fined \\ \\ \rm cot A & \rm Not \: De fined & \sqrt{3} & 1 & \dfrac{1}{ \sqrt{3} } & 0 \end{array}$