SOLUTION: This is a 3-part question. 1) Solve the following equation. Which of its values from the interval 0-180 degrees are correct? sin^2a + 1.5sina = 1 a) 30 degrees, 150 degrees

Algebra.Com
Question 767520: This is a 3-part question.
1) Solve the following equation. Which of its values from the interval 0-180 degrees are correct? sin^2a + 1.5sina = 1
a) 30 degrees, 150 degrees; b) 45 degrees, 120 degrees; c) 60 degrees, 150 degrees; d) 30 degrees, 110 degrees.
2) Why can't we use the solution sina = -2 of the equation?
3) Solve also the equation sin^2a - 1.5sina = 1.
I do not know how to even begin to solve this problem. If you are unable to help me, could you recommend where I might look for help as I cannot find anything about it on the Internet.

Answer by solver91311(24713)   (Show Source): You can put this solution on YOUR website!



Let , then



Solve the quadratic, which factors:



Then substitute back, so



or



Discard the root because the range of the function is

Using the unit circle:



The value of for an angle is the -coordinate of the point of intersection of the terminal ray of the angle and the unit circle. So find the two points in the desired interval where the -coordinate equals

Solve your other problem the same way, but you might want to reconsider the interval for your solutions if you are going to have any solutions at all.

John

My calculator said it, I believe it, that settles it
The Out Campaign: Scarlet Letter of Atheism


RELATED QUESTIONS

Solve the following equation algebraically for all values of theta in the interval 0... (answered by Fombitz,nyc_function)
Find to the nearest degree, all values of theta in the interval 0 degrees is < or equal... (answered by lwsshak3)
How many different values of x from 0 to 180 degrees for the equation (2sinx-1)... (answered by ikleyn)
Please can you help me solve the following question {{{find the two values of theta in... (answered by Fombitz)
Arrange the steps in the correct order to solve this trigonometric equation.... (answered by Solver92311,ikleyn)
So, I am currently studying for a Math1 Subject Test coming up using this awesome... (answered by Alan3354)
Find all values of x that satisfy the equation 2cosx-1=0, in the interval [0, 2pi] The (answered by ikleyn,MathLover1)
Polynomials Retail companies must keep close track of their operations to maintain... (answered by richard1234)
Find to the nearest degree all values of theta in the interval 0 degrees is less than or... (answered by stanbon)