Polynomials and Trig Help (1 Viewer)

[feedmemore]

HI

I need help with these questions, I attempted it but recieved the wrong answer. Can you guys please show me the correct working out.

Thanks

 

[HeroicPandas]

First one



Let the roots be: -3, 4,



Second one
a) Do sin(2theta + 2theta) = ... or let u = 2theta and expand...

sin(4θ) = 4 sin θ cos^3θ − 4 sin^3θ cos θ

b)

 

[iBibah]

First one



Let the roots be: -3, 4,



Second one
a) Do sin(2theta + 2theta) = ... or let u = 2theta and expand...

sin(4θ) = 4 sin θ cos^3θ − 4 sin^3θ cos θ

b)

x^2+4x+3 is not a linear factor.

 

[HeroicPandas]

x^2+4x+3 is not a linear factor.

turn it into (x+3)(x+1) then, Psyduck!

 

[Praer]

x^2+4x+3 is not a linear factor.

isn't this 4unit?

 

[Nws m8]

isn't this 4unit?

no

 

[copynpaste]

trig help please!

 

[HeroicPandas]

View attachment 28136

trig help please!

tan (135) = -tan (180 - 135) = -tan (45) = -1





Please don't be angry, i didnt label each part because it didn't come out what i desired

 

[copynpaste]

thanks! just wondering, where do you get cambridge worked solutions?

 

[copynpaste]

Also,

 

[HeroicPandas]

(a)




(b)too hard, its my bedtime bye

 

[braintic]

Also,
View attachment 28137

Using the fact that sin(4pi/5)=sin(pi/5) and cos (4pi/7)=-cos(3pi/7) [complementary ratios] it should then be easy using the double angle results.

It doesn't need the result given below.