√2sinx-√2cosx=2
That would be false. It equals -1. If thats what your asking.
I do not know, the teacher asked to solve this equation at home
I would assume she's asking for the solution to that problem, which would be \[ x= 3\pi / 4 \text{ or } x = 135 \text{ degrees} \]
Or more exactly ;), \[x=\frac{3\pi}{4}+2\pi k\] \[k=0,1,\ldots\]
Dividing through by the square root gives you \[ sin(x) - cos(x) = \sqrt{2} \] Squaring both sides will give you \[\sin^2(x) + cos^2(x) - 2\sin(x)\cos(x) = 2 \] but the first part of that is 1, so that means \[ 1 - 2\sin(x)\cos(x) = 2 \implies 2\sin(x)\cos(x) =-1\] Your trigonometry identities should tell you that \[2 \sin(x)\cos(x) = \sin(2x) \] So then \[ \sin(2x) = -1 \] the sine function is -1 at 3pi /2, so \[2x = \frac{3\pi}{2} \implies x = \frac{3\pi}{4} \]
Thank you very much!
Join our real-time social learning platform and learn together with your friends!