##
solve the equation 8xsquared+2x-3=0 hence solve the equation 8cos^2y+2cosy_3=0 for the range 0degrees

Question

Lost your password? Please enter your email address. You will receive a link and will create a new password via email.

Lorem ipsum dolor sit amet, consectetur adipiscing elit.Morbi adipiscing gravdio, sit amet suscipit risus ultrices eu.Fusce viverra neque at purus laoreet consequa.Vivamus vulputate posuere nisl quis consequat.

## Answers ( No )

8x^2 + 2x – 3 = 0

(4x )(2x )

(4x + 3)(2x – 1) = 0

Surprise: that might actually work.

4x + 3 =0

4x = – 3

x = – 3/4 That would be between 90 and 180 because the cos(x) is minus in quad 2.

2x – 1 = 0

2x = 1

x = 1/2 This one is actually only in quad 1.

cos(y) = 1/2

y = 60 degrees.

cos(y) = – 3/4

y = 138.6 degrees. You could do this by

cos(y) = 3/4

cos(y) = 41.4 degrees. Because the 3/4 is minus, the angle is in quad 2

180 – 41.4 = 138.6. Same answer.

The calculator does in the following way.

2nd F

Cos-1(

– 0.75

)

=

which will give you 138.6 immediately.