In[214]:= eq3 = NSolve[{eq1 == 0, 0 < \[Lambda] < 100}, \[Lambda]]
Out[214]= {{\[Lambda] -> 0.901317}, {\[Lambda] ->
2.38046}, {\[Lambda] -> 3.96149}, {\[Lambda] ->
7.16348}, {\[Lambda] -> 8.76828}, {\[Lambda] ->
10.3734}, {\[Lambda] -> 11.9785}, {\[Lambda] ->
13.5832}, {\[Lambda] -> 15.1875}, {\[Lambda] ->
16.7915}, {\[Lambda] -> 18.3949}, {\[Lambda] ->
19.9979}, {\[Lambda] -> 21.6003}, {\[Lambda] ->
23.2024}, {\[Lambda] -> 24.8039}, {\[Lambda] ->
26.405}, {\[Lambda] -> 28.0056}, {\[Lambda] ->
29.6057}, {\[Lambda] -> 31.2055}, {\[Lambda] ->
32.8047}, {\[Lambda] -> 34.4036}, {\[Lambda] ->
36.002}, {\[Lambda] -> 37.6001}, {\[Lambda] ->
39.1977}, {\[Lambda] -> 40.795}, {\[Lambda] ->
42.392}, {\[Lambda] -> 43.9885}, {\[Lambda] ->
45.5848}, {\[Lambda] -> 47.1807}, {\[Lambda] ->
48.7762}, {\[Lambda] -> 50.3715}, {\[Lambda] ->
51.9665}, {\[Lambda] -> 53.5612}, {\[Lambda] ->
55.1557}, {\[Lambda] -> 56.7499}, {\[Lambda] ->
58.3438}, {\[Lambda] -> 59.9375}, {\[Lambda] ->
61.531}, {\[Lambda] -> 63.1242}, {\[Lambda] ->
64.7172}, {\[Lambda] -> 66.3101}, {\[Lambda] ->
67.9027}, {\[Lambda] -> 69.4951}, {\[Lambda] ->
71.0874}, {\[Lambda] -> 72.6795}, {\[Lambda] ->
74.2714}, {\[Lambda] -> 75.8632}, {\[Lambda] ->
77.4548}, {\[Lambda] -> 79.0463}, {\[Lambda] ->
80.6376}, {\[Lambda] -> 82.2288}, {\[Lambda] ->
83.8198}, {\[Lambda] -> 85.4108}, {\[Lambda] ->
87.0016}, {\[Lambda] -> 88.5923}, {\[Lambda] ->
90.1828}, {\[Lambda] -> 91.7733}, {\[Lambda] ->
93.3637}, {\[Lambda] -> 94.954}, {\[Lambda] ->
96.5441}, {\[Lambda] -> 98.1342}, {\[Lambda] -> 99.7242}}