Which of the following is a solution to sin(2x) - cos x=0

Mathematics

1 answer:

dangina [55]3 years ago

6 0

$\sin2x-\cos x=0\ \ \ |\text{use:}\ \sin2x=2\sin x\cos x\\\\2\sin x\cos x-\cos x=0\\\\\cos x(2\sin x-1)=0\iff\cos x=0\ \vee\ 2\sin x-1=0\\\\(1)\ \cos x=0\to x=90^0\ \vee\ x=270^o\\\\(2)\ 2\sin x-1=0\ \ \ |+1\\2\sin x=1\ \ \ |:2\\\sin x=\frac{1}{2}\to x=30^o\ \vee\ x=150^o\\\\Answer:\ B.)\ 90^o.$

You might be interested in

If your cell phone bill was 67 Point $82 and there is a 7.5% late fee how much will your bill be with the late fee included

Ivenika [448]

$\frac{7.5}{100} = \frac{x}{82} \\ x = \frac{82 \times 7.5}{100} = \frac{615}{100 } = 6.15$
$82 + 6.15 = 88.15$
the answer is $88.15

7 0

3 years ago

In a random sample of 200 cars of a particular model,

Aleks04 [339]

By using proportions, We expect 150 defects out of the 10,000 cars if the 3 defects out of the 200 cars sampled is representative of all 10,000 cars.

Option A is correct.

First, let's set up the proportions.

A proportion is an equation in which two ratios are set equal to each other.

We have 3/200 cars with defects and we want to know X for X/10000.

So 3/200 = X/10000

Now solve for X.

3/200 = X/10000

X = $\frac{3}{200} \times 10000$