Core 2 Maths help please!

it's not a difficult question but i just don't get it for some reason..

6cos^2(theta) - sin(theta) - 5 = 0

the reason i can't get it is because of the fact 6cos^2(theta) isn't 5cos^2(theta)...
thankkkssss : )

Reply 1

J_Alom

using the rule: sin^2x + cos^x =1 , rearrange and:

6cos^2(theta) becomes: 6(1-sin^2x) = 6 - 6sin^2

replace with 6 - 6sin^2 and solve!

Reply 2

lagoom

J_Alom

using the rule: sin^2x + cos^x =1 , rearrange and:

6cos^2(theta) becomes: 6(1-sin^2x) = 6 - 6sin^2

replace with 6 - 6sin^2 and solve!

yeah i get that

6(1-sin^2x) - sinx - 5 = 0
6-6sin^2x - sinx - 5 = 0
now i can't get the equation to equal 0 because it 6 and 5, and when the equation equals 1 i don't know how to solve it

Reply 3

TomatoKetchup

You would add the 6 and the -5 together. Would equal 1.
Therefore, wouldn't it be:::: -6sin^2x - sinx +1= 0
And then put it into factorised form?
You'll see the two values of sinx. Then you can figure out x :p: