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2 years ago

Can someone help me pls

Mathematics

1 answer:

irina [24]2 years ago

3 0

Answer:

(d) x = (5±√53)/2

Step-by-step explanation:

The given quadratic equation is in standard form, so the coefficients are readily identified. The solution is given by the quadratic formula based on those coefficients.

<h3>Quadratic formula</h3>

The solution to the quadratic equation ax² +bx +c = 0 is given by the formula ...

$x=\dfrac{-b\pm\sqrt{b^2-4ac}}{2a}$

<h3>Application</h3>

The given equation has coefficients a = 1, b = -5, c = -7, so the solutions given by the formula are ...

$x=\dfrac{-(-5)\pm\sqrt{(-5)^2-4(1)(-7)}}{2(1)}=\dfrac{5\pm\sqrt{25+28}}{2}\\\\\boxed{x=\dfrac{5\pm\sqrt{53}}{2}}$

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Futhe Mathematics <img src="https://tex.z-dn.net/?f=%28Cos%20%7B%7D%5E%7B4%7Dt%20-Sin%20%7B%7D%5E%7B4%7Dt%20%29%20%20%5Cdiv%2

Nastasia [14]

Answer:

cos2t/cos²t

Step-by-step explanation:

Here the given trigonometric expression to us is ,

$\longrightarrow \dfrac{cos^4t - sin^4t }{cos^2t }$

We can write the numerator as ,

$\longrightarrow \dfrac{ (cos^2t)^2-(sin^2t)^2}{cos^2t }$

Recall the identity ,

$\longrightarrow (a-b)(a+b)=a^2-b^2$

Using this we have ,

$\longrightarrow \dfrac{(cos^2t + sin^2t)(cos^2t-sin^2t)}{cos^2t}$

Again , as we know that ,

$\longrightarrow sin^2\phi + cos^2\phi = 1$

Therefore we can rewrite it as ,

$\longrightarrow \dfrac{1(cos^2t - sin^2t)}{cos^2t}$

Again using the first identity mentioned above ,

$\longrightarrow \underline{\underline{\dfrac{(cost + sint )(cost - sint)}{cos^2t}}}$

Or else we can also write it using ,

$\longrightarrow cos2\phi = cos^2\phi - sin^2\phi$

Therefore ,

$\longrightarrow \underline{\underline{\dfrac{cos2t}{cos^2t}}}$

And we are done !

$\rule{200}{4}$

Additional info :-

Derivation of cos²x - sin²x = cos2x :-

We can rewrite cos 2x as ,

$\longrightarrow cos(x + x )$

As we know that ,

$\longrightarrow cos(y + z )= cosy.cosz - siny.sinz$

So that ,

$\longrightarrow cos(x+x) = cos(x).cos(x) - sin(x)sin(x)$

On simplifying,

$\longrightarrow cos(x+x) = cos^2x - sin^2x$

Hence,

$\longrightarrow\underline{\underline{cos (2x) = cos^2x - sin^2x }}$

$\rule{200}{4}$

7 0

3 years ago

You do not need to line up the decimal points when subtracting two decimal numbers.

marta [7]

Your answer is false. hope that helped

8 0

4 years ago

Read 2 more answers

Someone please help me it would mean alot !!

myrzilka [38]

Answer:

y intercept ( 0, 0.4)

x intercept ( 0.3, 0)

Step-by-step explanation:

The y intercept is where is crosses the y axis and the x value is zero

(0, 0.4)

The x intercept is where is crosses the x axis and the y value is zero

(0.3,0)

4 0

3 years ago

This is as far as I got can you check my work so far and tell me where to go from here

umka21 [38]

You did a simple mistake by forgetting to add 4 to itself in the square root. (-4^2=16)

x=(4 +/- sqrt(16-8))/4
x=(4 +/- sqrt(8))/4

Is this enough to get you started again?

8 0

3 years ago

Use this picture for all Make sure 1-4 is correct and the answer to 5

qwelly [4]

I can't answer cause u didn't show the angles

3 0

4 years ago