Question

3 sec theta - 2 cos theta =5 find theta.
plz answer​

Answer 1

Answer:

3sec theta - 2cos theta = 5

3(1/cos theta) - 2cos theta = 5

3-2cos^2theta/cos theta= 5

3 -2cos^2 theta = 5cos theta

therefore,

2cos^2 theta + 5cos theta - 3 = 0

2cos^2 theta + 6cos theta - cos theta - 3 = 0

2cos theta(cos theta + 3) - 1(cos theta + 3)

(2cos theta - 1) (cos theta + 3)

cos theta =1/2,3

therefore, cos theta = 1/2

hence, theta = 60°

Answer 2

Answer:

1. or,3 1/cos theta -2 cos theta = 5

• or,3/cos theta - 2 cos theta =5

Do L.C.M, we get;

• or, 3-2 cos sq.theta /coss theta = 5
• or, 3- cos square theta =5 cos theta
• or, - 2 cos square theta - 5 cos theta +3=0
• or, -(2 cos square theta +5 cos theta -3)=0
• or, 2 cos square theta +5 cos theta -3=0
• 2 cos square theta +(6-1) cos theta -3 =.
• 2 cos square theta +6 cos theta - 1 cos theta -3=0
• 2 cos theta (cos theta +3)-1(cos+3)=0
• (cos theta +3)(2 cos theta -1 )=0

Either- Or,

cos theta +3=0. 2 cos theta -1=0

cos theta =-3. 2 cos theta =1

• cos theta =1/2=cos 60 degree.

therefore: theta=60 degree(Answer)