$$y=y_m\sin\left[2\pi\left(\frac{t}{T}-\frac{x}{\lambda}\right)\right]$$  

$$y=y_m\cos\left[2\alpha\left(l-\frac{x}{\pi}\right)\right]$$  

$$y=y_m\sin\left[2\lambda\left(\frac{t}{T}-x\right)\right]$$  

$$y=y_m\sin\left[2\pi\left(\frac{t}{T}+\frac{x}{\lambda}\right)\right]$$  

$$d=\left(2k\ -\ 1\right)\frac{\lambda}{2}$$  

$$d=2k\frac{\lambda}{2}$$  

$$d=\frac{\lambda}{2}+1$$  

$$d=\left(2k+1\right)\frac{\lambda}{2}$$  

$$\frac{1}{a}+\frac{1}{a'}=\frac{1}{f}$$   

$$\frac{1}{a}-\frac{1}{a'}=\frac{1}{f}$$  

$$\frac{1}{f}=\left(1-\frac{n_2}{n_1}\right)\left(\frac{1}{r_1^2}+\frac{1}{r_2^2}\right)$$  

$$\frac{1}{f}=\left(\frac{n_2}{n_1}-1\right)\left(\frac{1}{r_1}+\frac{1}{r_2}\right)$$  

$$Z=\frac{y'}{y}$$  

$$Z=-\frac{y}{y'}$$  

$$Z=\frac{a'}{a}$$  

$$Z=-\frac{a'}{a}$$  

$$Z=\frac{a'}{y}$$  

$$Z=-\frac{f}{a-f}$$  

$$Z=-\frac{a'-f}{f-a}$$  

$$Z=\frac{a'-f}{f}$$  

$$Z=\frac{f}{a-f}$$  

$$Z=-\frac{a'-f}{f}$$  

$$φ=\frac{1}{f}−1$$  

$$φ=\frac{1}{f}$$  

$$φ=f-a$$  

$$φ=f^2$$  

$$γ=\frac{τ}{τ'}$$  

$$γ=\frac{τ}{τ'}-1$$  

$$γ=\frac{τ\ '}{τ}$$  

$$γ=\frac{τ-1}{τ'}$$  

$$γ=\frac{φ}{l}$$  

$$γ=φ\cdot l$$  

$$γ=φ\cdot\sqrt[]{l}$$  

$$γ=\frac{φ^2}{\sqrt[]{l}}$$  

$$γ=γ2\cdotγ1$$  

$$\gamma=\frac{Z}{f}$$  

$$γ=\frac{φ}{Z}$$  

$$\gamma=Z\cdot\gamma_2$$  

$$\gamma=\frac{f_2}{f_1}$$  

$$\gamma=\frac{\tau}{f_2-f_1}$$  

$$y=\frac{f_1}{f_2}$$  

$$y=-\frac{f_1^2}{f_2}$$  

$$d=(2k−1)\ \frac{\lambda}{2}$$  

$$d=\frac{\lambda}{2}+1$$  

$$d=2k\frac{\lambda}{2}$$  

$$d=(2k+1)\frac{\lambda}{2}$$  

$$n=\frac{\sinα​}{\sinβ}=\frac{​v_1​​}{v_2}$$  

$$n=\frac{\sin\beta​}{\sin\alpha}=\frac{​v_1​​}{v_2}$$  

$$n=\frac{\cosα​}{\cosβ}=\frac{​v_1​​}{v_2}$$  

$$n=\frac{tg\ α​}{tg\ β}=\frac{​v_1​​}{v_2}$$  

$$\frac{a}{1}+\frac{a′}{1}​​=\frac{f}{1}​​$$  

$$d=2k\frac{λ}{2}​​$$  

$$γ=\frac{f2}{f1}​$$  

$$n=\frac{c}{v}​=\sqrt[]{\epsilon_rr_r}​\ge1$$  

Snell's law

Relative refractive index of light

Absolute refractive index of light

Transverse magnification