Ask question

Ask question

All categories

3 years ago

11

What is the cosine of 135 degrees?

2 answers:

Varvara68 [4.7K]3 years ago

7 0

$cos(180^0- \alpha )=-cos \alpha \\ \\ cos135^0=cos(180^0-45^0)=-cos45^0=- \frac{ \sqrt{2} }{2}$

belka [17]3 years ago

3 0

$cos135^o=cos(90^o+45^o)=-sin45^o=-\frac{\sqrt2}{2}\\\\reduction\ formulas:\ cos(90^o+\alpha)=-sin\alpha$

You might be interested in

Evelyn has dance class every Saturday. It lasts 1 hour and 40 minutes and is over at 12:45 P.M.

leva [86]

Answer:

Evelyn's dance class on Saturday starts at 11:05 A.M.

Step-by-step explanation:

I know this because if her class takes an hour and 40 minutes you would subtract the hour and 40 minutes from 12:45 so you could do 12 - 1 which equals 11. Then you would do 45 - 40 which equals 5. And last you would put the new times together so it would be, 11:05. Her dance class starts at 11:05 A.M.

7 0

3 years ago

What is the volume of the composite figure. I said 36 but it is wrong.

scZoUnD [109]

Answer:

108

Step-by-step explanation:

You are correct for stating one tissue box has a volume for 36.

But notice there are 3 tissue boxes, so in order to find the total volume, you should add them up.

36+36+36=108

6 0

3 years ago

Read 2 more answers

A rocket is launched from a tower. The height of the rocket, y in feet, is related to the time after launch, x in seconds, by th

irga5000 [103]

Answer:

The rocket hits the ground at a time of 11.59 seconds.

Step-by-step explanation:

The height of the rocket, after x seconds, is given by the following equation:

$y = -16x^2 + 177x + 98$

It hits the ground when $y = 0$ , so we have to find x for which $y = 0$ , which is a quadratic equation.

Finding the roots of a quadratic equation:

Given a second order polynomial expressed by the following equation:

$ax^{2} + bx + c, a\neq0$ .

This polynomial has roots $x_{1}, x_{2}$ such that $ax^{2} + bx + c = a(x - x_{1})*(x - x_{2})$ , given by the following formulas:

$x_{1} = \frac{-b + \sqrt{\bigtriangleup}}{2*a}$

$x_{2} = \frac{-b - \sqrt{\bigtriangleup}}{2*a}$

$\bigtriangleup = b^{2} - 4ac$

In this question:

$y = -16x^2 + 177x + 98$

$-16x^2 + 177x + 98 = 0$

So

$a = -16, b = 177, c = 98$

$\bigtriangleup = 177^{2} - 4(-16)(98) = 37601$

$x_{1} = \frac{-177 + \sqrt{37601}}{2*(-16)} = -0.53$

$x_{2} = \frac{-177 - \sqrt{37601}}{2*(-16)} = 11.59$

Since time is a positive measure, the rocket hits the ground at a time of 11.59 seconds.

4 0

3 years ago

A teacher has a container of paper clips. She will randomly select one paper clip from the container.

laila [671]

Answer:

D

Step-by-step explanation:

There are 50 clips and 14 of them are purple.

Probability of picking purple is 14/50 or 7/25. Probability of picking non purple is 1 - 7/25 = 18/25

7 0

2 years ago

Read 2 more answers

Find missing number sequence 1,2,5,10,13,__,__,58,61

lys-0071 [83]

The pattern is *2 +3 *2 +3 *2 +3 .... 1 *2 = 2 , 2+3 = 5 , 5 *2 = 10, 10 +3 = 13, 13*2 = ?...

7 0

3 years ago