This one is so easy that your brain refuses to accept it.
It's looking for a harder answer, but can't find it !

You're totally correct, as far you went.    x² + 2x does = -1

Now add ' 1 ' to each side:   x² + 2x + 1 = 0

Can you factor that quadratic ?
Can you mash it through the quadratic formula ?

Actually, it's the simplest possible perfect square.

   x² + 2x + 1 = (x + 1)²

So the solutions of   x² + 2x + 1 = 0 are both   x = -1 .

Don't say anything.
I know it's embarrassing.

7 0

3 years ago

In the month of June, the temperature in Johannesburg, South Africa, varies over the day in a periodic way that can be modeled a

Art [367]

Answer:

The answer is " $\bold{T = - 7.5 \cos \frac{\pi}{12}( t - 4 )+ 10.5}$ "

Step-by-step explanation:

Given value:

Temp-maximum= $18^{\circ}$

Temp. minimum = $3^{\circ}$

It is halfway between 10 am and 10 pm to 4 am.

The sinus and cosine roles could be used throughout the year to predict fluctuations in climate models. Its type of formula that can be used to model such information is:

$T = A \cos B(t-C) + D,$ where parameters are A, B , C, D, T is the ° C temperature and t is the time (1-24)