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3 years ago

Help me with math please ><

Mathematics

1 answer:

nikklg [1K]3 years ago

7 0

I can't see it. Too blurry

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Cos^2x+cos^2(120°+x)+cos^2(120°-x)<br>i need this asap. pls help me

o-na [289]

Answer:

$\frac{3}{2}$

Step-by-step explanation:

Using the addition formulae for cosine

cos(x ± y) = cosxcosy ∓ sinxsiny

---------------------------------------------------------------

cos(120 + x) = cos120cosx - sin120sinx

= - cos60cosx - sin60sinx

= - $\frac{1}{2}$ cosx - $\frac{\sqrt{3} }{2}$ sinx

squaring to obtain cos² (120 + x)

= $\frac{1}{4}$ cos²x + $\frac{\sqrt{3} }{2}$ sinxcosx + $\frac{3}{4}$ sin²x

--------------------------------------------------------------------

cos(120 - x) = cos120cosx + sin120sinx

= -cos60cosx + sin60sinx

= - $\frac{1}{2}$ cosx + $\frac{\sqrt{3} }{2}$ sinx

squaring to obtain cos²(120 - x)

= $\frac{1}{4}$ cos²x - $\frac{\sqrt{3} }{2}$ sinxcosx + $\frac{3}{4}$ sin²x

--------------------------------------------------------------------------

Putting it all together

cos²x + $\frac{1}{4}$ cos²x + $\frac{\sqrt{3} }{2}$ sinxcosx + $\frac{3}{4}$ sin²x + $\frac{1}{4}$ cos²x - $\frac{\sqrt{3} }{2}$ sinxcosx + $\frac{3}{4}$ sin²x

= cos²x + $\frac{1}{2}$ cos²x + $\frac{3}{2}$ sin²x

= $\frac{3}{2}$ cos²x + $\frac{3}{2}$ sin²x

= $\frac{3}{2}$ (cos²x + sin²x) = $\frac{3}{2}$

5 0

3 years ago

Someone please help!

Mila [183]

Answer:

RU is 8

Step-by-step explanation:

4 0

3 years ago

What is thirty-seven and nine tenths written in expanded form

xeze [42]

37.9 equals 30+7+.9 you should try to put in number form so you know what you're dealing with

3 0

3 years ago

Read 2 more answers

The current in a simple electrical circuit is inversely proportional to the resistance. The current is 80 amps when the resistan

Oksana_A [137]

I = / r where I = current and r = resistance

80 = k / 50 so
k = 400

so we have I = 400/r

when r = 40
I = 400/40 = 10 amps

6 0

3 years ago

WHO CAN HELP ME WITH THIS QUESTION PLEASE PLEASE PLEASE

natima [27]

Answer:

105.12

Step-by-step explanation:

6 0

3 years ago