Sin² x + sin x cos x = 0
sin x ( sin x + cos x ) = 0
sin x = 0 ; x 1 = k π ; k ∈ Z
sin x + cos x = 0 / ²
sin² x + 2 sin x cos x + cos² x = 0
2 sin x cos x + 1 =0
sin ( 2 x ) = - 1
x = 3π / 2 + 2 kπ / : 2
x 2 = 3π / 4 + kπ ; k ∈ Z
Answer:
- 1.25 hours or 1 hour and 15 minutes
Step-by-step explanation:
<em>Question</em>
- <em>Lisa lit a candle with a height of 8 inches. When lit, this candle loses 10% of its original height every hour. </em>
- <em>Please complete the following sentence by writing the number in the blank.
Until the candle has been burning for at least _______ hours, the height of Jennifer's candle will be more than 7 inches.</em>
<u>Candle looses 10% of 8 inches, it equals:</u>
- 8*0.1 = 0.8 inches an hour
<u>Let x be required time, then:</u>
- 8 - 0.8x > 7
- 0.8x < 8 - 7
- 0.8x < 1
- x < 1/0.8
- x < 1.25
- or 1 hour 15 minutes
Answer:
(9+3i)-(2-7i)=17i
Step-by-step explanation:
