Find values of x in the interval 0<x<360 degrees. For which 5sin^2(x) + 5 sin(x) +4 cos^2(x)=0
This question is split up into two parts.
Firstly recall the trigonometric identities you know, the trick here is to eliminate one of the squared terms. Using 4sin^2(x) +4cos^2(x) = 4, the cos term is eliminated.
Rearranging this equation leaves you with a strange quadratic equation, but if you pretend sin is x it actually looks quite simple and can be solved like a simple quadratic. Solve like this and replace x for sin and the solution follows
JG
Related Maths A Level answers
All answers ▸Determine the coordinates of all the stationary points of the function f(x) = (1/3)*x^3+x^2-3*x+1 and state whether they are a maximum or a minimum.
How do you find the minimum of the equation sin^2(x) + 4sin(x)?
Compute the indefinite integral of x^8 ln(3x)dx
Find the values of x where the curve y = 8 -4x-2x^2 crosses the x-axis.